diff --git a/fe-admin/src/components/pe/PeDetailTabs.tsx b/fe-admin/src/components/pe/PeDetailTabs.tsx
index e7ecbb9..9277017 100644
--- a/fe-admin/src/components/pe/PeDetailTabs.tsx
+++ b/fe-admin/src/components/pe/PeDetailTabs.tsx
@@ -158,6 +158,18 @@ function InfoTab({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: bool
         <Field label="Mô tả" value={ev.moTa ?? '—'} />
         <Field label="NCC được chọn" value={ev.selectedSupplierName ?? '—'} />
         <Field label="Điều khoản thanh toán" value={ev.paymentTerms ?? '—'} />
+        <Field
+          label="Ngân sách"
+          value={ev.budget ? (
+            <a href={`/budgets?id=${ev.budget.id}`} className="text-brand-600 hover:underline">
+              <span className="font-mono text-[11px]">{ev.budget.maNganSach ?? '—'}</span>
+              {' · '}
+              {ev.budget.tenNganSach}
+              {' · '}
+              <span className="text-slate-500">{ev.budget.tongNganSach.toLocaleString('vi-VN')} đ</span>
+            </a>
+          ) : <span className="text-slate-400">— (chưa link)</span>}
+        />
         {ev.contractId && (
           <Field label="HĐ kế thừa" value={<a href={`/contracts/${ev.contractId}`} className="text-brand-600 hover:underline">✓ Xem HĐ</a>} />
         )}
@@ -471,6 +483,25 @@ function ItemsTab({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: boo
   const quoteKey = (detailId: string, supplierRowId: string) =>
     ev.details.find(d => d.id === detailId)?.quotes.find(q => q.purchaseEvaluationSupplierId === supplierRowId) ?? null
 
+  // Budget comparison — fetch full Budget bundle nếu có link để so sánh per-row.
+  // Match key: groupCode|itemCode (case-sensitive match; itemCode null cho phép).
+  const budgetBundle = useQuery({
+    queryKey: ['budget-detail-for-pe', ev.budgetId],
+    queryFn: async () => (await api.get<{ details: { groupCode: string; itemCode: string | null; thanhTien: number }[]; tongNganSach: number }>(
+      `/budgets/${ev.budgetId}`)).data,
+    enabled: !!ev.budgetId,
+  })
+  const budgetRowMap = (() => {
+    const m = new Map<string, number>()
+    budgetBundle.data?.details.forEach(d => {
+      m.set(`${d.groupCode}|${d.itemCode ?? ''}`, d.thanhTien)
+    })
+    return m
+  })()
+  const showBudgetCol = !!ev.budgetId
+  const totalPeNganSach = ev.details.reduce((sum, d) => sum + d.thanhTienNganSach, 0)
+  const totalBudget = budgetBundle.data?.tongNganSach ?? 0
+
   return (
     <div>
       <div className="mb-3 flex items-center justify-between">
@@ -499,6 +530,11 @@ function ItemsTab({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: boo
                 <th className="border-r border-slate-200 px-2 py-2 text-right">KL</th>
                 <th className="border-r border-slate-200 px-2 py-2 text-right">ĐG ngân sách</th>
                 <th className="border-r border-slate-200 px-2 py-2 text-right">TT ngân sách</th>
+                {showBudgetCol && (
+                  <th className="border-r border-slate-200 bg-amber-50 px-2 py-2 text-right" title="So với ngân sách đã link">
+                    NS link · Δ
+                  </th>
+                )}
                 {ev.suppliers.map(s => (
                   <th key={s.id} className="border-r border-slate-200 px-2 py-2 text-right">
                     {s.displayName ?? s.supplierName}
@@ -517,6 +553,26 @@ function ItemsTab({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: boo
                   <td className="border-r border-slate-200 px-2 py-2 text-right font-mono">{d.khoiLuongNganSach}</td>
                   <td className="border-r border-slate-200 px-2 py-2 text-right font-mono">{fmtMoney(d.donGiaNganSach)}</td>
                   <td className="border-r border-slate-200 px-2 py-2 text-right font-mono">{fmtMoney(d.thanhTienNganSach)}</td>
+                  {showBudgetCol && (() => {
+                    const bgValue = budgetRowMap.get(`${d.groupCode}|${d.itemCode ?? ''}`)
+                    if (bgValue == null)
+                      return <td className="border-r border-slate-200 bg-amber-50/40 px-2 py-2 text-right text-slate-300">—</td>
+                    const delta = d.thanhTienNganSach - bgValue
+                    return (
+                      <td
+                        className={cn(
+                          'border-r border-slate-200 bg-amber-50/40 px-2 py-2 text-right font-mono',
+                          delta > 0 && 'text-red-600',
+                          delta < 0 && 'text-emerald-600',
+                          delta === 0 && 'text-slate-500',
+                        )}
+                        title={`Ngân sách: ${fmtMoney(bgValue)} · Δ ${delta > 0 ? '+' : ''}${fmtMoney(delta)}`}
+                      >
+                        {fmtMoney(bgValue)}
+                        <div className="text-[10px]">{delta === 0 ? '=' : (delta > 0 ? `+${fmtMoney(delta)}` : fmtMoney(delta))}</div>
+                      </td>
+                    )
+                  })()}
                   {ev.suppliers.map(s => {
                     const q = quoteKey(d.id, s.id)
                     return (
@@ -548,6 +604,34 @@ function ItemsTab({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: boo
                 </tr>
               ))}
             </tbody>
+            {showBudgetCol && (
+              <tfoot className="border-t-2 border-slate-300 bg-slate-50 text-xs font-semibold">
+                <tr>
+                  <td className="sticky left-0 z-10 border-r border-slate-200 bg-slate-50 px-2 py-2 text-right">Tổng:</td>
+                  <td className="border-r border-slate-200"></td>
+                  <td className="border-r border-slate-200"></td>
+                  <td className="border-r border-slate-200 px-2 py-2 text-right font-mono">{fmtMoney(totalPeNganSach)}</td>
+                  <td className="border-r border-slate-200 bg-amber-50 px-2 py-2 text-right font-mono">
+                    {fmtMoney(totalBudget)}
+                    {(() => {
+                      const delta = totalPeNganSach - totalBudget
+                      return (
+                        <div className={cn(
+                          'text-[10px]',
+                          delta > 0 && 'text-red-600',
+                          delta < 0 && 'text-emerald-600',
+                          delta === 0 && 'text-slate-500',
+                        )}>
+                          {delta === 0 ? 'khớp ngân sách' : delta > 0 ? `vượt +${fmtMoney(delta)}` : `dưới ${fmtMoney(delta)}`}
+                        </div>
+                      )
+                    })()}
+                  </td>
+                  {ev.suppliers.map(s => <td key={s.id} className="border-r border-slate-200" />)}
+                  {!readOnly && <td />}
+                </tr>
+              </tfoot>
+            )}
           </table>
         </div>
       )}
diff --git a/fe-admin/src/pages/contracts/ContractCreatePage.tsx b/fe-admin/src/pages/contracts/ContractCreatePage.tsx
index afdf556..6d3d889 100644
--- a/fe-admin/src/pages/contracts/ContractCreatePage.tsx
+++ b/fe-admin/src/pages/contracts/ContractCreatePage.tsx
@@ -35,6 +35,7 @@ import {
   type ContractDetail,
   type ContractListItem,
 } from '@/types/contracts'
+import { BudgetPhase, type BudgetListItem } from '@/types/budget'
 
 const fmtMoney = (v: number) => v.toLocaleString('vi-VN')
 
@@ -303,9 +304,12 @@ function ContractHeaderForm({
   const [tenHopDong, setTenHopDong] = useState('')
   const [noiDung, setNoiDung] = useState('')
   const [bypass, setBypass] = useState(false)
+  const [budgetId, setBudgetId] = useState('')
 
   // Reset type về default khi typeFilter (parent prop) thay đổi
   useEffect(() => { setType(defaultType) }, [defaultType])
+  // Reset budget khi đổi project (mỗi project có ngân sách riêng)
+  useEffect(() => { setBudgetId('') }, [projectId])
 
   const suppliers = useQuery({
     queryKey: ['suppliers-all'],
@@ -319,6 +323,15 @@ function ContractHeaderForm({
     queryKey: ['templates-by-type', type],
     queryFn: async () => (await api.get<ContractTemplate[]>('/forms/templates', { params: { type } })).data,
   })
+  // Eligible Budgets: cùng Project + Phase=DaDuyet (BE-side filter).
+  const eligibleBudgets = useQuery({
+    queryKey: ['eligible-budgets', projectId],
+    queryFn: async () =>
+      (await api.get<Paged<BudgetListItem>>('/budgets', {
+        params: { pageSize: 100, projectId, phase: BudgetPhase.DaDuyet },
+      })).data.items,
+    enabled: !!projectId,
+  })
 
   const qc = useQueryClient()
   const create = useMutation({
@@ -334,6 +347,7 @@ function ContractHeaderForm({
         noiDung: noiDung || null,
         bypassProcurementAndCCM: bypass,
         draftData: null,
+        budgetId: budgetId || null,
       })
       return res.data.id
     },
@@ -372,6 +386,28 @@ function ContractHeaderForm({
           templates={templates.data ?? []}
           typeReadonly={false}
         />
+        <div className="mt-4 space-y-1.5">
+          <Label>Ngân sách (đối chiếu chi phí)</Label>
+          <Select
+            value={budgetId}
+            disabled={!projectId}
+            onChange={e => setBudgetId(e.target.value)}
+          >
+            <option value="">— (không link)</option>
+            {eligibleBudgets.data?.map(b => (
+              <option key={b.id} value={b.id}>
+                {b.maNganSach ?? '—'} · {b.tenNganSach} · {b.tongNganSach.toLocaleString('vi-VN')} đ
+              </option>
+            ))}
+          </Select>
+          <p className="text-[11px] text-slate-500">
+            {!projectId
+              ? 'Chọn dự án trước để xem ngân sách khả dụng.'
+              : eligibleBudgets.data && eligibleBudgets.data.length === 0
+              ? 'Dự án này chưa có ngân sách đã duyệt.'
+              : 'Chỉ list ngân sách đã duyệt cùng dự án.'}
+          </p>
+        </div>
         <div className="mt-4 flex justify-end gap-2">
           <Button type="submit" disabled={create.isPending}>
             <Save className="h-4 w-4" />
@@ -460,11 +496,21 @@ function ContractEditForm({
   const [giaTri, setGiaTri] = useState(String(contract.giaTri ?? 0))
   const [tenHopDong, setTenHopDong] = useState(contract.tenHopDong ?? '')
   const [noiDung, setNoiDung] = useState(contract.noiDung ?? '')
+  const [budgetId, setBudgetId] = useState(contract.budgetId ?? '')
 
   const templates = useQuery({
     queryKey: ['templates-by-type', contract.type],
     queryFn: async () => (await api.get<ContractTemplate[]>('/forms/templates', { params: { type: contract.type } })).data,
   })
+  // Eligible Budgets: cùng Project + Phase=DaDuyet
+  const eligibleBudgets = useQuery({
+    queryKey: ['eligible-budgets', contract.projectId],
+    queryFn: async () =>
+      (await api.get<Paged<BudgetListItem>>('/budgets', {
+        params: { pageSize: 100, projectId: contract.projectId, phase: BudgetPhase.DaDuyet },
+      })).data.items,
+    enabled: isDraft,
+  })
 
   const qc = useQueryClient()
   const update = useMutation({
@@ -476,6 +522,7 @@ function ContractEditForm({
         noiDung: noiDung || null,
         templateId: templateId || null,
         draftData: null,
+        budgetId: budgetId || null,
       })
     },
     onSuccess: () => {
@@ -563,6 +610,37 @@ function ContractEditForm({
             <Label>Nội dung / ghi chú</Label>
             <Textarea rows={4} value={noiDung} onChange={e => setNoiDung(e.target.value)} disabled={!isDraft} />
           </div>
+          <div className="col-span-2 space-y-1.5">
+            <Label>Ngân sách (đối chiếu chi phí)</Label>
+            {isDraft ? (
+              <>
+                <Select value={budgetId} onChange={e => setBudgetId(e.target.value)}>
+                  <option value="">— (không link)</option>
+                  {eligibleBudgets.data?.map(b => (
+                    <option key={b.id} value={b.id}>
+                      {b.maNganSach ?? '—'} · {b.tenNganSach} · {b.tongNganSach.toLocaleString('vi-VN')} đ
+                    </option>
+                  ))}
+                </Select>
+                <p className="text-[11px] text-slate-500">
+                  {eligibleBudgets.data && eligibleBudgets.data.length === 0
+                    ? 'Dự án này chưa có ngân sách đã duyệt.'
+                    : 'Chỉ list ngân sách đã duyệt cùng dự án.'}
+                </p>
+              </>
+            ) : contract.budget ? (
+              <a
+                href={`/budgets?id=${contract.budget.id}`}
+                className="block rounded border border-slate-200 bg-slate-50 px-3 py-2 text-sm text-slate-700 hover:bg-brand-50 hover:text-brand-700"
+              >
+                <span className="font-mono text-[11px]">{contract.budget.maNganSach ?? '—'}</span>
+                {' · '}{contract.budget.tenNganSach}
+                {' · '}<span className="text-slate-500">{contract.budget.tongNganSach.toLocaleString('vi-VN')} đ</span>
+              </a>
+            ) : (
+              <Input value="(không link)" disabled className="bg-slate-50" />
+            )}
+          </div>
         </div>
       </div>
 
diff --git a/fe-admin/src/pages/pe/PurchaseEvaluationCreatePage.tsx b/fe-admin/src/pages/pe/PurchaseEvaluationCreatePage.tsx
index b385430..4312e18 100644
--- a/fe-admin/src/pages/pe/PurchaseEvaluationCreatePage.tsx
+++ b/fe-admin/src/pages/pe/PurchaseEvaluationCreatePage.tsx
@@ -17,7 +17,8 @@ import {
   PurchaseEvaluationTypeLabel,
   type PeDetailBundle,
 } from '@/types/purchaseEvaluation'
-import type { Project } from '@/types/master'
+import { BudgetPhase, type BudgetListItem } from '@/types/budget'
+import type { Paged, Project } from '@/types/master'
 
 export function PurchaseEvaluationCreatePage() {
   const navigate = useNavigate()
@@ -43,6 +44,24 @@ export function PurchaseEvaluationCreatePage() {
     diaDiem: '',
     moTa: '',
     paymentTerms: '',
+    budgetId: '' as string,
+  })
+
+  // Eligible Budgets: cùng Project + Phase=DaDuyet. BE filter trên Project +
+  // Phase server-side để FE không phải lọc thêm.
+  const eligibleBudgets = useQuery({
+    queryKey: ['eligible-budgets', form.projectId],
+    queryFn: async () => {
+      const res = await api.get<Paged<BudgetListItem>>('/budgets', {
+        params: {
+          pageSize: 100,
+          projectId: form.projectId,
+          phase: BudgetPhase.DaDuyet,
+        },
+      })
+      return res.data.items
+    },
+    enabled: !!form.projectId,
   })
 
   useEffect(() => {
@@ -54,6 +73,7 @@ export function PurchaseEvaluationCreatePage() {
         diaDiem: existing.data.diaDiem ?? '',
         moTa: existing.data.moTa ?? '',
         paymentTerms: existing.data.paymentTerms ?? '',
+        budgetId: existing.data.budgetId ?? '',
       })
     }
   }, [existing.data])
@@ -67,6 +87,7 @@ export function PurchaseEvaluationCreatePage() {
           diaDiem: form.diaDiem || null,
           moTa: form.moTa || null,
           paymentTerms: form.paymentTerms || null,
+          budgetId: form.budgetId || null,
         })
       }
       return api.post<{ id: string }>('/purchase-evaluations', {
@@ -76,6 +97,7 @@ export function PurchaseEvaluationCreatePage() {
         diaDiem: form.diaDiem || null,
         moTa: form.moTa || null,
         paymentTerms: form.paymentTerms || null,
+        budgetId: form.budgetId || null,
       })
     },
     onSuccess: res => {
@@ -133,6 +155,29 @@ export function PurchaseEvaluationCreatePage() {
           </Select>
         </div>
 
+        <div>
+          <Label>Ngân sách (đối chiếu chi phí)</Label>
+          <Select
+            value={form.budgetId}
+            disabled={!form.projectId}
+            onChange={e => setForm({ ...form, budgetId: e.target.value })}
+          >
+            <option value="">— (không link)</option>
+            {eligibleBudgets.data?.map(b => (
+              <option key={b.id} value={b.id}>
+                {b.maNganSach ?? '—'} · {b.tenNganSach} · {b.tongNganSach.toLocaleString('vi-VN')} đ
+              </option>
+            ))}
+          </Select>
+          <p className="mt-1 text-[11px] text-slate-500">
+            {!form.projectId
+              ? 'Chọn dự án trước để xem ngân sách khả dụng.'
+              : eligibleBudgets.data && eligibleBudgets.data.length === 0
+              ? 'Dự án này chưa có ngân sách đã duyệt.'
+              : 'Chỉ list ngân sách đã duyệt cùng dự án.'}
+          </p>
+        </div>
+
         <div>
           <Label>Địa điểm</Label>
           <Input
diff --git a/fe-admin/src/types/contracts.ts b/fe-admin/src/types/contracts.ts
index 67aa771..fdf04e1 100644
--- a/fe-admin/src/types/contracts.ts
+++ b/fe-admin/src/types/contracts.ts
@@ -101,6 +101,16 @@ export type WorkflowSummary = {
   nextPhases: number[]
 }
 
+// Snapshot ngân sách link cho Contract (cùng shape với BudgetSummaryDto BE).
+export type ContractBudgetSummary = {
+  id: string
+  maNganSach: string | null
+  tenNganSach: string
+  namNganSach: number
+  phase: number
+  tongNganSach: number
+}
+
 export type ContractDetail = {
   id: string
   maHopDong: string | null
@@ -123,6 +133,8 @@ export type ContractDetail = {
   draftData: string | null
   createdAt: string
   updatedAt: string | null
+  budgetId: string | null
+  budget: ContractBudgetSummary | null
   approvals: ContractApproval[]
   comments: ContractComment[]
   attachments: ContractAttachment[]
diff --git a/fe-admin/src/types/purchaseEvaluation.ts b/fe-admin/src/types/purchaseEvaluation.ts
index 76a5980..25a3c77 100644
--- a/fe-admin/src/types/purchaseEvaluation.ts
+++ b/fe-admin/src/types/purchaseEvaluation.ts
@@ -165,6 +165,16 @@ export type PeChangelog = {
   createdAt: string
 }
 
+// Snapshot ngân sách link (compact — cùng shape BudgetSummaryDto BE).
+export type BudgetSummary = {
+  id: string
+  maNganSach: string | null
+  tenNganSach: string
+  namNganSach: number
+  phase: number
+  tongNganSach: number
+}
+
 export type PeDetailBundle = {
   id: string
   maPhieu: string | null
@@ -186,6 +196,8 @@ export type PeDetailBundle = {
   slaDeadline: string | null
   createdAt: string
   updatedAt: string | null
+  budgetId: string | null
+  budget: BudgetSummary | null
   suppliers: PeSupplier[]
   details: PeDetailRow[]
   approvals: PeApproval[]
diff --git a/fe-user/src/components/pe/PeDetailTabs.tsx b/fe-user/src/components/pe/PeDetailTabs.tsx
index e7ecbb9..9277017 100644
--- a/fe-user/src/components/pe/PeDetailTabs.tsx
+++ b/fe-user/src/components/pe/PeDetailTabs.tsx
@@ -158,6 +158,18 @@ function InfoTab({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: bool
         <Field label="Mô tả" value={ev.moTa ?? '—'} />
         <Field label="NCC được chọn" value={ev.selectedSupplierName ?? '—'} />
         <Field label="Điều khoản thanh toán" value={ev.paymentTerms ?? '—'} />
+        <Field
+          label="Ngân sách"
+          value={ev.budget ? (
+            <a href={`/budgets?id=${ev.budget.id}`} className="text-brand-600 hover:underline">
+              <span className="font-mono text-[11px]">{ev.budget.maNganSach ?? '—'}</span>
+              {' · '}
+              {ev.budget.tenNganSach}
+              {' · '}
+              <span className="text-slate-500">{ev.budget.tongNganSach.toLocaleString('vi-VN')} đ</span>
+            </a>
+          ) : <span className="text-slate-400">— (chưa link)</span>}
+        />
         {ev.contractId && (
           <Field label="HĐ kế thừa" value={<a href={`/contracts/${ev.contractId}`} className="text-brand-600 hover:underline">✓ Xem HĐ</a>} />
         )}
@@ -471,6 +483,25 @@ function ItemsTab({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: boo
   const quoteKey = (detailId: string, supplierRowId: string) =>
     ev.details.find(d => d.id === detailId)?.quotes.find(q => q.purchaseEvaluationSupplierId === supplierRowId) ?? null
 
+  // Budget comparison — fetch full Budget bundle nếu có link để so sánh per-row.
+  // Match key: groupCode|itemCode (case-sensitive match; itemCode null cho phép).
+  const budgetBundle = useQuery({
+    queryKey: ['budget-detail-for-pe', ev.budgetId],
+    queryFn: async () => (await api.get<{ details: { groupCode: string; itemCode: string | null; thanhTien: number }[]; tongNganSach: number }>(
+      `/budgets/${ev.budgetId}`)).data,
+    enabled: !!ev.budgetId,
+  })
+  const budgetRowMap = (() => {
+    const m = new Map<string, number>()
+    budgetBundle.data?.details.forEach(d => {
+      m.set(`${d.groupCode}|${d.itemCode ?? ''}`, d.thanhTien)
+    })
+    return m
+  })()
+  const showBudgetCol = !!ev.budgetId
+  const totalPeNganSach = ev.details.reduce((sum, d) => sum + d.thanhTienNganSach, 0)
+  const totalBudget = budgetBundle.data?.tongNganSach ?? 0
+
   return (
     <div>
       <div className="mb-3 flex items-center justify-between">
@@ -499,6 +530,11 @@ function ItemsTab({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: boo
                 <th className="border-r border-slate-200 px-2 py-2 text-right">KL</th>
                 <th className="border-r border-slate-200 px-2 py-2 text-right">ĐG ngân sách</th>
                 <th className="border-r border-slate-200 px-2 py-2 text-right">TT ngân sách</th>
+                {showBudgetCol && (
+                  <th className="border-r border-slate-200 bg-amber-50 px-2 py-2 text-right" title="So với ngân sách đã link">
+                    NS link · Δ
+                  </th>
+                )}
                 {ev.suppliers.map(s => (
                   <th key={s.id} className="border-r border-slate-200 px-2 py-2 text-right">
                     {s.displayName ?? s.supplierName}
@@ -517,6 +553,26 @@ function ItemsTab({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: boo
                   <td className="border-r border-slate-200 px-2 py-2 text-right font-mono">{d.khoiLuongNganSach}</td>
                   <td className="border-r border-slate-200 px-2 py-2 text-right font-mono">{fmtMoney(d.donGiaNganSach)}</td>
                   <td className="border-r border-slate-200 px-2 py-2 text-right font-mono">{fmtMoney(d.thanhTienNganSach)}</td>
+                  {showBudgetCol && (() => {
+                    const bgValue = budgetRowMap.get(`${d.groupCode}|${d.itemCode ?? ''}`)
+                    if (bgValue == null)
+                      return <td className="border-r border-slate-200 bg-amber-50/40 px-2 py-2 text-right text-slate-300">—</td>
+                    const delta = d.thanhTienNganSach - bgValue
+                    return (
+                      <td
+                        className={cn(
+                          'border-r border-slate-200 bg-amber-50/40 px-2 py-2 text-right font-mono',
+                          delta > 0 && 'text-red-600',
+                          delta < 0 && 'text-emerald-600',
+                          delta === 0 && 'text-slate-500',
+                        )}
+                        title={`Ngân sách: ${fmtMoney(bgValue)} · Δ ${delta > 0 ? '+' : ''}${fmtMoney(delta)}`}
+                      >
+                        {fmtMoney(bgValue)}
+                        <div className="text-[10px]">{delta === 0 ? '=' : (delta > 0 ? `+${fmtMoney(delta)}` : fmtMoney(delta))}</div>
+                      </td>
+                    )
+                  })()}
                   {ev.suppliers.map(s => {
                     const q = quoteKey(d.id, s.id)
                     return (
@@ -548,6 +604,34 @@ function ItemsTab({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: boo
                 </tr>
               ))}
             </tbody>
+            {showBudgetCol && (
+              <tfoot className="border-t-2 border-slate-300 bg-slate-50 text-xs font-semibold">
+                <tr>
+                  <td className="sticky left-0 z-10 border-r border-slate-200 bg-slate-50 px-2 py-2 text-right">Tổng:</td>
+                  <td className="border-r border-slate-200"></td>
+                  <td className="border-r border-slate-200"></td>
+                  <td className="border-r border-slate-200 px-2 py-2 text-right font-mono">{fmtMoney(totalPeNganSach)}</td>
+                  <td className="border-r border-slate-200 bg-amber-50 px-2 py-2 text-right font-mono">
+                    {fmtMoney(totalBudget)}
+                    {(() => {
+                      const delta = totalPeNganSach - totalBudget
+                      return (
+                        <div className={cn(
+                          'text-[10px]',
+                          delta > 0 && 'text-red-600',
+                          delta < 0 && 'text-emerald-600',
+                          delta === 0 && 'text-slate-500',
+                        )}>
+                          {delta === 0 ? 'khớp ngân sách' : delta > 0 ? `vượt +${fmtMoney(delta)}` : `dưới ${fmtMoney(delta)}`}
+                        </div>
+                      )
+                    })()}
+                  </td>
+                  {ev.suppliers.map(s => <td key={s.id} className="border-r border-slate-200" />)}
+                  {!readOnly && <td />}
+                </tr>
+              </tfoot>
+            )}
           </table>
         </div>
       )}
diff --git a/fe-user/src/pages/contracts/ContractCreatePage.tsx b/fe-user/src/pages/contracts/ContractCreatePage.tsx
index afdf556..6d3d889 100644
--- a/fe-user/src/pages/contracts/ContractCreatePage.tsx
+++ b/fe-user/src/pages/contracts/ContractCreatePage.tsx
@@ -35,6 +35,7 @@ import {
   type ContractDetail,
   type ContractListItem,
 } from '@/types/contracts'
+import { BudgetPhase, type BudgetListItem } from '@/types/budget'
 
 const fmtMoney = (v: number) => v.toLocaleString('vi-VN')
 
@@ -303,9 +304,12 @@ function ContractHeaderForm({
   const [tenHopDong, setTenHopDong] = useState('')
   const [noiDung, setNoiDung] = useState('')
   const [bypass, setBypass] = useState(false)
+  const [budgetId, setBudgetId] = useState('')
 
   // Reset type về default khi typeFilter (parent prop) thay đổi
   useEffect(() => { setType(defaultType) }, [defaultType])
+  // Reset budget khi đổi project (mỗi project có ngân sách riêng)
+  useEffect(() => { setBudgetId('') }, [projectId])
 
   const suppliers = useQuery({
     queryKey: ['suppliers-all'],
@@ -319,6 +323,15 @@ function ContractHeaderForm({
     queryKey: ['templates-by-type', type],
     queryFn: async () => (await api.get<ContractTemplate[]>('/forms/templates', { params: { type } })).data,
   })
+  // Eligible Budgets: cùng Project + Phase=DaDuyet (BE-side filter).
+  const eligibleBudgets = useQuery({
+    queryKey: ['eligible-budgets', projectId],
+    queryFn: async () =>
+      (await api.get<Paged<BudgetListItem>>('/budgets', {
+        params: { pageSize: 100, projectId, phase: BudgetPhase.DaDuyet },
+      })).data.items,
+    enabled: !!projectId,
+  })
 
   const qc = useQueryClient()
   const create = useMutation({
@@ -334,6 +347,7 @@ function ContractHeaderForm({
         noiDung: noiDung || null,
         bypassProcurementAndCCM: bypass,
         draftData: null,
+        budgetId: budgetId || null,
       })
       return res.data.id
     },
@@ -372,6 +386,28 @@ function ContractHeaderForm({
           templates={templates.data ?? []}
           typeReadonly={false}
         />
+        <div className="mt-4 space-y-1.5">
+          <Label>Ngân sách (đối chiếu chi phí)</Label>
+          <Select
+            value={budgetId}
+            disabled={!projectId}
+            onChange={e => setBudgetId(e.target.value)}
+          >
+            <option value="">— (không link)</option>
+            {eligibleBudgets.data?.map(b => (
+              <option key={b.id} value={b.id}>
+                {b.maNganSach ?? '—'} · {b.tenNganSach} · {b.tongNganSach.toLocaleString('vi-VN')} đ
+              </option>
+            ))}
+          </Select>
+          <p className="text-[11px] text-slate-500">
+            {!projectId
+              ? 'Chọn dự án trước để xem ngân sách khả dụng.'
+              : eligibleBudgets.data && eligibleBudgets.data.length === 0
+              ? 'Dự án này chưa có ngân sách đã duyệt.'
+              : 'Chỉ list ngân sách đã duyệt cùng dự án.'}
+          </p>
+        </div>
         <div className="mt-4 flex justify-end gap-2">
           <Button type="submit" disabled={create.isPending}>
             <Save className="h-4 w-4" />
@@ -460,11 +496,21 @@ function ContractEditForm({
   const [giaTri, setGiaTri] = useState(String(contract.giaTri ?? 0))
   const [tenHopDong, setTenHopDong] = useState(contract.tenHopDong ?? '')
   const [noiDung, setNoiDung] = useState(contract.noiDung ?? '')
+  const [budgetId, setBudgetId] = useState(contract.budgetId ?? '')
 
   const templates = useQuery({
     queryKey: ['templates-by-type', contract.type],
     queryFn: async () => (await api.get<ContractTemplate[]>('/forms/templates', { params: { type: contract.type } })).data,
   })
+  // Eligible Budgets: cùng Project + Phase=DaDuyet
+  const eligibleBudgets = useQuery({
+    queryKey: ['eligible-budgets', contract.projectId],
+    queryFn: async () =>
+      (await api.get<Paged<BudgetListItem>>('/budgets', {
+        params: { pageSize: 100, projectId: contract.projectId, phase: BudgetPhase.DaDuyet },
+      })).data.items,
+    enabled: isDraft,
+  })
 
   const qc = useQueryClient()
   const update = useMutation({
@@ -476,6 +522,7 @@ function ContractEditForm({
         noiDung: noiDung || null,
         templateId: templateId || null,
         draftData: null,
+        budgetId: budgetId || null,
       })
     },
     onSuccess: () => {
@@ -563,6 +610,37 @@ function ContractEditForm({
             <Label>Nội dung / ghi chú</Label>
             <Textarea rows={4} value={noiDung} onChange={e => setNoiDung(e.target.value)} disabled={!isDraft} />
           </div>
+          <div className="col-span-2 space-y-1.5">
+            <Label>Ngân sách (đối chiếu chi phí)</Label>
+            {isDraft ? (
+              <>
+                <Select value={budgetId} onChange={e => setBudgetId(e.target.value)}>
+                  <option value="">— (không link)</option>
+                  {eligibleBudgets.data?.map(b => (
+                    <option key={b.id} value={b.id}>
+                      {b.maNganSach ?? '—'} · {b.tenNganSach} · {b.tongNganSach.toLocaleString('vi-VN')} đ
+                    </option>
+                  ))}
+                </Select>
+                <p className="text-[11px] text-slate-500">
+                  {eligibleBudgets.data && eligibleBudgets.data.length === 0
+                    ? 'Dự án này chưa có ngân sách đã duyệt.'
+                    : 'Chỉ list ngân sách đã duyệt cùng dự án.'}
+                </p>
+              </>
+            ) : contract.budget ? (
+              <a
+                href={`/budgets?id=${contract.budget.id}`}
+                className="block rounded border border-slate-200 bg-slate-50 px-3 py-2 text-sm text-slate-700 hover:bg-brand-50 hover:text-brand-700"
+              >
+                <span className="font-mono text-[11px]">{contract.budget.maNganSach ?? '—'}</span>
+                {' · '}{contract.budget.tenNganSach}
+                {' · '}<span className="text-slate-500">{contract.budget.tongNganSach.toLocaleString('vi-VN')} đ</span>
+              </a>
+            ) : (
+              <Input value="(không link)" disabled className="bg-slate-50" />
+            )}
+          </div>
         </div>
       </div>
 
diff --git a/fe-user/src/pages/pe/PurchaseEvaluationCreatePage.tsx b/fe-user/src/pages/pe/PurchaseEvaluationCreatePage.tsx
index b385430..4312e18 100644
--- a/fe-user/src/pages/pe/PurchaseEvaluationCreatePage.tsx
+++ b/fe-user/src/pages/pe/PurchaseEvaluationCreatePage.tsx
@@ -17,7 +17,8 @@ import {
   PurchaseEvaluationTypeLabel,
   type PeDetailBundle,
 } from '@/types/purchaseEvaluation'
-import type { Project } from '@/types/master'
+import { BudgetPhase, type BudgetListItem } from '@/types/budget'
+import type { Paged, Project } from '@/types/master'
 
 export function PurchaseEvaluationCreatePage() {
   const navigate = useNavigate()
@@ -43,6 +44,24 @@ export function PurchaseEvaluationCreatePage() {
     diaDiem: '',
     moTa: '',
     paymentTerms: '',
+    budgetId: '' as string,
+  })
+
+  // Eligible Budgets: cùng Project + Phase=DaDuyet. BE filter trên Project +
+  // Phase server-side để FE không phải lọc thêm.
+  const eligibleBudgets = useQuery({
+    queryKey: ['eligible-budgets', form.projectId],
+    queryFn: async () => {
+      const res = await api.get<Paged<BudgetListItem>>('/budgets', {
+        params: {
+          pageSize: 100,
+          projectId: form.projectId,
+          phase: BudgetPhase.DaDuyet,
+        },
+      })
+      return res.data.items
+    },
+    enabled: !!form.projectId,
   })
 
   useEffect(() => {
@@ -54,6 +73,7 @@ export function PurchaseEvaluationCreatePage() {
         diaDiem: existing.data.diaDiem ?? '',
         moTa: existing.data.moTa ?? '',
         paymentTerms: existing.data.paymentTerms ?? '',
+        budgetId: existing.data.budgetId ?? '',
       })
     }
   }, [existing.data])
@@ -67,6 +87,7 @@ export function PurchaseEvaluationCreatePage() {
           diaDiem: form.diaDiem || null,
           moTa: form.moTa || null,
           paymentTerms: form.paymentTerms || null,
+          budgetId: form.budgetId || null,
         })
       }
       return api.post<{ id: string }>('/purchase-evaluations', {
@@ -76,6 +97,7 @@ export function PurchaseEvaluationCreatePage() {
         diaDiem: form.diaDiem || null,
         moTa: form.moTa || null,
         paymentTerms: form.paymentTerms || null,
+        budgetId: form.budgetId || null,
       })
     },
     onSuccess: res => {
@@ -133,6 +155,29 @@ export function PurchaseEvaluationCreatePage() {
           </Select>
         </div>
 
+        <div>
+          <Label>Ngân sách (đối chiếu chi phí)</Label>
+          <Select
+            value={form.budgetId}
+            disabled={!form.projectId}
+            onChange={e => setForm({ ...form, budgetId: e.target.value })}
+          >
+            <option value="">— (không link)</option>
+            {eligibleBudgets.data?.map(b => (
+              <option key={b.id} value={b.id}>
+                {b.maNganSach ?? '—'} · {b.tenNganSach} · {b.tongNganSach.toLocaleString('vi-VN')} đ
+              </option>
+            ))}
+          </Select>
+          <p className="mt-1 text-[11px] text-slate-500">
+            {!form.projectId
+              ? 'Chọn dự án trước để xem ngân sách khả dụng.'
+              : eligibleBudgets.data && eligibleBudgets.data.length === 0
+              ? 'Dự án này chưa có ngân sách đã duyệt.'
+              : 'Chỉ list ngân sách đã duyệt cùng dự án.'}
+          </p>
+        </div>
+
         <div>
           <Label>Địa điểm</Label>
           <Input
diff --git a/fe-user/src/types/contracts.ts b/fe-user/src/types/contracts.ts
index 67aa771..fdf04e1 100644
--- a/fe-user/src/types/contracts.ts
+++ b/fe-user/src/types/contracts.ts
@@ -101,6 +101,16 @@ export type WorkflowSummary = {
   nextPhases: number[]
 }
 
+// Snapshot ngân sách link cho Contract (cùng shape với BudgetSummaryDto BE).
+export type ContractBudgetSummary = {
+  id: string
+  maNganSach: string | null
+  tenNganSach: string
+  namNganSach: number
+  phase: number
+  tongNganSach: number
+}
+
 export type ContractDetail = {
   id: string
   maHopDong: string | null
@@ -123,6 +133,8 @@ export type ContractDetail = {
   draftData: string | null
   createdAt: string
   updatedAt: string | null
+  budgetId: string | null
+  budget: ContractBudgetSummary | null
   approvals: ContractApproval[]
   comments: ContractComment[]
   attachments: ContractAttachment[]
diff --git a/fe-user/src/types/purchaseEvaluation.ts b/fe-user/src/types/purchaseEvaluation.ts
index 76a5980..25a3c77 100644
--- a/fe-user/src/types/purchaseEvaluation.ts
+++ b/fe-user/src/types/purchaseEvaluation.ts
@@ -165,6 +165,16 @@ export type PeChangelog = {
   createdAt: string
 }
 
+// Snapshot ngân sách link (compact — cùng shape BudgetSummaryDto BE).
+export type BudgetSummary = {
+  id: string
+  maNganSach: string | null
+  tenNganSach: string
+  namNganSach: number
+  phase: number
+  tongNganSach: number
+}
+
 export type PeDetailBundle = {
   id: string
   maPhieu: string | null
@@ -186,6 +196,8 @@ export type PeDetailBundle = {
   slaDeadline: string | null
   createdAt: string
   updatedAt: string | null
+  budgetId: string | null
+  budget: BudgetSummary | null
   suppliers: PeSupplier[]
   details: PeDetailRow[]
   approvals: PeApproval[]
diff --git a/src/Backend/SolutionErp.Application/Budgets/Dtos/BudgetDtos.cs b/src/Backend/SolutionErp.Application/Budgets/Dtos/BudgetDtos.cs
index 5fb984f..e3fcf02 100644
--- a/src/Backend/SolutionErp.Application/Budgets/Dtos/BudgetDtos.cs
+++ b/src/Backend/SolutionErp.Application/Budgets/Dtos/BudgetDtos.cs
@@ -57,6 +57,17 @@ public record BudgetWorkflowSummaryDto(
     List<BudgetPhase> ActivePhases,
     List<BudgetPhase> NextPhases);
 
+// Snapshot ngân sách link cho PE / Contract DetailBundle. Compact — chỉ
+// header info, không bao gồm BudgetDetails (gọi /budgets/{id} riêng nếu cần
+// đối chiếu chi tiết theo từng GroupCode/ItemCode).
+public record BudgetSummaryDto(
+    Guid Id,
+    string? MaNganSach,
+    string TenNganSach,
+    int NamNganSach,
+    BudgetPhase Phase,
+    decimal TongNganSach);
+
 public record BudgetDetailBundleDto(
     Guid Id,
     string? MaNganSach,
diff --git a/src/Backend/SolutionErp.Application/Contracts/ContractFeatures.cs b/src/Backend/SolutionErp.Application/Contracts/ContractFeatures.cs
index 30d47b7..5d8274a 100644
--- a/src/Backend/SolutionErp.Application/Contracts/ContractFeatures.cs
+++ b/src/Backend/SolutionErp.Application/Contracts/ContractFeatures.cs
@@ -24,7 +24,8 @@ public record CreateContractCommand(
     string? TenHopDong,
     string? NoiDung,
     bool BypassProcurementAndCCM,
-    string? DraftData) : IRequest<Guid>;
+    string? DraftData,
+    Guid? BudgetId) : IRequest<Guid>;
 
 public class CreateContractCommandValidator : AbstractValidator<CreateContractCommand>
 {
@@ -59,6 +60,18 @@ public class CreateContractCommandHandler(
             .Select(w => (Guid?)w.Id)
             .FirstOrDefaultAsync(ct);
 
+        // Validate Budget link nếu có: cùng Project + Phase=DaDuyet.
+        if (request.BudgetId is Guid bid)
+        {
+            var bg = await db.Budgets.AsNoTracking()
+                .FirstOrDefaultAsync(b => b.Id == bid, ct)
+                ?? throw new NotFoundException("Budget", bid);
+            if (bg.ProjectId != request.ProjectId)
+                throw new ConflictException("Ngân sách phải cùng dự án với HĐ.");
+            if (bg.Phase != Domain.Budgets.BudgetPhase.DaDuyet)
+                throw new ConflictException("Chỉ link được ngân sách đã duyệt.");
+        }
+
         var entity = new Contract
         {
             Type = request.Type,
@@ -73,6 +86,7 @@ public class CreateContractCommandHandler(
             NoiDung = request.NoiDung,
             BypassProcurementAndCCM = request.BypassProcurementAndCCM,
             DraftData = request.DraftData,
+            BudgetId = request.BudgetId,
             WorkflowDefinitionId = activeWfId,
             SlaDeadline = DateTime.UtcNow.Add(workflow.GetPhaseSla(ContractPhase.DangSoanThao) ?? TimeSpan.FromDays(7)),
         };
@@ -106,7 +120,8 @@ public record UpdateContractDraftCommand(
     string? TenHopDong,
     string? NoiDung,
     Guid? TemplateId,
-    string? DraftData) : IRequest;
+    string? DraftData,
+    Guid? BudgetId) : IRequest;
 
 public class UpdateContractDraftCommandHandler(
     IApplicationDbContext db,
@@ -120,6 +135,18 @@ public class UpdateContractDraftCommandHandler(
         if (entity.Phase != ContractPhase.DangSoanThao)
             throw new ConflictException("Chỉ được sửa HĐ khi ở phase Đang soạn thảo.");
 
+        // Validate Budget link nếu thay đổi.
+        if (request.BudgetId is Guid bid && bid != entity.BudgetId)
+        {
+            var bg = await db.Budgets.AsNoTracking()
+                .FirstOrDefaultAsync(b => b.Id == bid, ct)
+                ?? throw new NotFoundException("Budget", bid);
+            if (bg.ProjectId != entity.ProjectId)
+                throw new ConflictException("Ngân sách phải cùng dự án với HĐ.");
+            if (bg.Phase != Domain.Budgets.BudgetPhase.DaDuyet)
+                throw new ConflictException("Chỉ link được ngân sách đã duyệt.");
+        }
+
         // Capture diff trước update để log
         var changes = new List<object>();
         if (entity.GiaTri != request.GiaTri)
@@ -130,12 +157,15 @@ public class UpdateContractDraftCommandHandler(
             changes.Add(new { Field = "NoiDung", Old = entity.NoiDung, New = request.NoiDung });
         if (entity.TemplateId != request.TemplateId)
             changes.Add(new { Field = "TemplateId", Old = entity.TemplateId, New = request.TemplateId });
+        if (entity.BudgetId != request.BudgetId)
+            changes.Add(new { Field = "BudgetId", Old = entity.BudgetId, New = request.BudgetId });
 
         entity.GiaTri = request.GiaTri;
         entity.TenHopDong = request.TenHopDong;
         entity.NoiDung = request.NoiDung;
         entity.TemplateId = request.TemplateId;
         entity.DraftData = request.DraftData;
+        entity.BudgetId = request.BudgetId;
 
         if (changes.Count > 0)
         {
@@ -393,6 +423,17 @@ public class GetContractQueryHandler(
         var project = await db.Projects.AsNoTracking().FirstOrDefaultAsync(p => p.Id == c.ProjectId, ct);
         var department = c.DepartmentId is null ? null : await db.Departments.AsNoTracking().FirstOrDefaultAsync(d => d.Id == c.DepartmentId, ct);
 
+        // Load Budget summary nếu có link.
+        Budgets.Dtos.BudgetSummaryDto? budgetSummary = null;
+        if (c.BudgetId is Guid budgetId)
+        {
+            budgetSummary = await db.Budgets.AsNoTracking()
+                .Where(b => b.Id == budgetId)
+                .Select(b => new Budgets.Dtos.BudgetSummaryDto(
+                    b.Id, b.MaNganSach, b.TenNganSach, b.NamNganSach, b.Phase, b.TongNganSach))
+                .FirstOrDefaultAsync(ct);
+        }
+
         // Resolve workflow: pinned WorkflowDefinition > overrides > hardcoded
         WorkflowPolicy workflowPolicy;
         if (c.WorkflowDefinitionId is Guid wfId)
@@ -429,6 +470,7 @@ public class GetContractQueryHandler(
             c.DrafterUserId, c.DrafterUserId is Guid d && users.TryGetValue(d, out var dn) ? dn : null,
             c.TemplateId, c.GiaTri, c.BypassProcurementAndCCM, c.SlaDeadline, c.DraftData,
             c.CreatedAt, c.UpdatedAt,
+            c.BudgetId, budgetSummary,
             c.Approvals
                 .OrderBy(a => a.ApprovedAt)
                 .Select(a => new ContractApprovalDto(
diff --git a/src/Backend/SolutionErp.Application/Contracts/Dtos/ContractDtos.cs b/src/Backend/SolutionErp.Application/Contracts/Dtos/ContractDtos.cs
index 1337248..b335361 100644
--- a/src/Backend/SolutionErp.Application/Contracts/Dtos/ContractDtos.cs
+++ b/src/Backend/SolutionErp.Application/Contracts/Dtos/ContractDtos.cs
@@ -1,3 +1,4 @@
+using SolutionErp.Application.Budgets.Dtos;
 using SolutionErp.Domain.Contracts;
 
 namespace SolutionErp.Application.Contracts.Dtos;
@@ -38,6 +39,8 @@ public record ContractDetailDto(
     string? DraftData,
     DateTime CreatedAt,
     DateTime? UpdatedAt,
+    Guid? BudgetId,
+    BudgetSummaryDto? Budget,
     List<ContractApprovalDto> Approvals,
     List<ContractCommentDto> Comments,
     List<ContractAttachmentDto> Attachments,
diff --git a/src/Backend/SolutionErp.Application/PurchaseEvaluations/CreateContractFromEvaluationFeatures.cs b/src/Backend/SolutionErp.Application/PurchaseEvaluations/CreateContractFromEvaluationFeatures.cs
index 6231c6b..d573f69 100644
--- a/src/Backend/SolutionErp.Application/PurchaseEvaluations/CreateContractFromEvaluationFeatures.cs
+++ b/src/Backend/SolutionErp.Application/PurchaseEvaluations/CreateContractFromEvaluationFeatures.cs
@@ -79,6 +79,7 @@ public class CreateContractFromEvaluationCommandHandler(
             NoiDung = pe.MoTa,
             BypassProcurementAndCCM = request.BypassProcurementAndCCM,
             DraftData = pe.PaymentTerms,   // carry forward payment terms
+            BudgetId = pe.BudgetId,        // carry forward Budget link nếu PE đã link
             WorkflowDefinitionId = activeWfId,
             SlaDeadline = DateTime.UtcNow.Add(
                 workflow.GetPhaseSla(ContractPhase.DangSoanThao) ?? TimeSpan.FromDays(7)),
diff --git a/src/Backend/SolutionErp.Application/PurchaseEvaluations/Dtos/PurchaseEvaluationDtos.cs b/src/Backend/SolutionErp.Application/PurchaseEvaluations/Dtos/PurchaseEvaluationDtos.cs
index 0f18805..a52b92a 100644
--- a/src/Backend/SolutionErp.Application/PurchaseEvaluations/Dtos/PurchaseEvaluationDtos.cs
+++ b/src/Backend/SolutionErp.Application/PurchaseEvaluations/Dtos/PurchaseEvaluationDtos.cs
@@ -1,3 +1,4 @@
+using SolutionErp.Application.Budgets.Dtos;
 using SolutionErp.Domain.Contracts;
 using SolutionErp.Domain.PurchaseEvaluations;
 
@@ -115,6 +116,8 @@ public record PurchaseEvaluationDetailBundleDto(
     DateTime? SlaDeadline,
     DateTime CreatedAt,
     DateTime? UpdatedAt,
+    Guid? BudgetId,
+    BudgetSummaryDto? Budget,
     List<PurchaseEvaluationSupplierDto> Suppliers,
     List<PurchaseEvaluationDetailDto> Details,
     List<PurchaseEvaluationApprovalDto> Approvals,
diff --git a/src/Backend/SolutionErp.Application/PurchaseEvaluations/PurchaseEvaluationFeatures.cs b/src/Backend/SolutionErp.Application/PurchaseEvaluations/PurchaseEvaluationFeatures.cs
index 51ba12e..c4dd91e 100644
--- a/src/Backend/SolutionErp.Application/PurchaseEvaluations/PurchaseEvaluationFeatures.cs
+++ b/src/Backend/SolutionErp.Application/PurchaseEvaluations/PurchaseEvaluationFeatures.cs
@@ -22,7 +22,8 @@ public record CreatePurchaseEvaluationCommand(
     Guid? DepartmentId,
     string? DiaDiem,
     string? MoTa,
-    string? PaymentTerms) : IRequest<Guid>;
+    string? PaymentTerms,
+    Guid? BudgetId) : IRequest<Guid>;
 
 public class CreatePurchaseEvaluationCommandValidator : AbstractValidator<CreatePurchaseEvaluationCommand>
 {
@@ -52,6 +53,19 @@ public class CreatePurchaseEvaluationCommandHandler(
             .Select(w => (Guid?)w.Id)
             .FirstOrDefaultAsync(ct);
 
+        // Validate Budget link (nếu có): cùng Project + Phase=DaDuyet (chỉ cho
+        // pick ngân sách đã duyệt mới được dùng làm reference đối chiếu).
+        if (request.BudgetId is Guid bid)
+        {
+            var bg = await db.Budgets.AsNoTracking()
+                .FirstOrDefaultAsync(b => b.Id == bid, ct)
+                ?? throw new NotFoundException("Budget", bid);
+            if (bg.ProjectId != request.ProjectId)
+                throw new ConflictException("Ngân sách phải cùng dự án với phiếu.");
+            if (bg.Phase != Domain.Budgets.BudgetPhase.DaDuyet)
+                throw new ConflictException("Chỉ link được ngân sách đã duyệt.");
+        }
+
         var entity = new PurchaseEvaluation
         {
             Type = request.Type,
@@ -64,6 +78,7 @@ public class CreatePurchaseEvaluationCommandHandler(
             DrafterUserId = currentUser.UserId,
             WorkflowDefinitionId = activeWfId,
             PaymentTerms = request.PaymentTerms,
+            BudgetId = request.BudgetId,
             SlaDeadline = DateTime.UtcNow.Add(
                 workflow.GetPhaseSla(PurchaseEvaluationPhase.DangSoanThao) ?? TimeSpan.FromDays(3)),
         };
@@ -96,7 +111,8 @@ public record UpdatePurchaseEvaluationDraftCommand(
     string TenGoiThau,
     string? DiaDiem,
     string? MoTa,
-    string? PaymentTerms) : IRequest;
+    string? PaymentTerms,
+    Guid? BudgetId) : IRequest;
 
 public class UpdatePurchaseEvaluationDraftCommandHandler(
     IApplicationDbContext db,
@@ -110,10 +126,23 @@ public class UpdatePurchaseEvaluationDraftCommandHandler(
         if (entity.Phase != PurchaseEvaluationPhase.DangSoanThao)
             throw new ConflictException("Chỉ sửa được phiếu khi ở phase Đang soạn thảo.");
 
+        // Validate Budget link nếu thay đổi.
+        if (request.BudgetId is Guid bid && bid != entity.BudgetId)
+        {
+            var bg = await db.Budgets.AsNoTracking()
+                .FirstOrDefaultAsync(b => b.Id == bid, ct)
+                ?? throw new NotFoundException("Budget", bid);
+            if (bg.ProjectId != entity.ProjectId)
+                throw new ConflictException("Ngân sách phải cùng dự án với phiếu.");
+            if (bg.Phase != Domain.Budgets.BudgetPhase.DaDuyet)
+                throw new ConflictException("Chỉ link được ngân sách đã duyệt.");
+        }
+
         entity.TenGoiThau = request.TenGoiThau;
         entity.DiaDiem = request.DiaDiem;
         entity.MoTa = request.MoTa;
         entity.PaymentTerms = request.PaymentTerms;
+        entity.BudgetId = request.BudgetId;
 
         db.PurchaseEvaluationChangelogs.Add(new PurchaseEvaluationChangelog
         {
@@ -329,6 +358,17 @@ public class GetPurchaseEvaluationQueryHandler(
         var department = e.DepartmentId is null ? null : await db.Departments.AsNoTracking().FirstOrDefaultAsync(d => d.Id == e.DepartmentId, ct);
         var selectedSupplier = e.SelectedSupplierId is null ? null : await db.Suppliers.AsNoTracking().FirstOrDefaultAsync(s => s.Id == e.SelectedSupplierId, ct);
 
+        // Load Budget summary nếu có link
+        Budgets.Dtos.BudgetSummaryDto? budgetSummary = null;
+        if (e.BudgetId is Guid budgetId)
+        {
+            budgetSummary = await db.Budgets.AsNoTracking()
+                .Where(b => b.Id == budgetId)
+                .Select(b => new Budgets.Dtos.BudgetSummaryDto(
+                    b.Id, b.MaNganSach, b.TenNganSach, b.NamNganSach, b.Phase, b.TongNganSach))
+                .FirstOrDefaultAsync(ct);
+        }
+
         // Load supplier names for PE suppliers + approver names
         var supplierIds = e.Suppliers.Select(s => s.SupplierId).ToList();
         var suppliers = await db.Suppliers.AsNoTracking().Where(s => supplierIds.Contains(s.Id))
@@ -366,6 +406,7 @@ public class GetPurchaseEvaluationQueryHandler(
             e.SelectedSupplierId, selectedSupplier?.Name,
             e.ContractId,
             e.PaymentTerms, e.SlaDeadline, e.CreatedAt, e.UpdatedAt,
+            e.BudgetId, budgetSummary,
             e.Suppliers
                 .OrderBy(s => s.Order)
                 .Select(s => new PurchaseEvaluationSupplierDto(