diff --git a/frontend/src/pages/SocialInsurance.tsx b/frontend/src/pages/SocialInsurance.tsx
index 2ec33e3..90971e0 100644
--- a/frontend/src/pages/SocialInsurance.tsx
+++ b/frontend/src/pages/SocialInsurance.tsx
@@ -1105,6 +1105,21 @@ function SpecialDeductionTab({ month, setMonth }: { month: string; setMonth: (m:
     },
   })
 
+  // 查询上月专项附加扣除数据（用于「复制上月」功能）
+  const prevMonth = (() => {
+    const [y, m] = month.split('-').map(Number)
+    const d = new Date(y, m - 2, 1)
+    return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}`
+  })()
+  const { data: prevRecords = [] } = useQuery<any[]>({
+    queryKey: ['special-deduction', prevMonth],
+    queryFn: async () => {
+      const res = await api.get('/social/special-deduction/batch', { params: { month: prevMonth } }) as any
+      return res.data || []
+    },
+  })
+  const prevRecordMap = new Map(prevRecords.map((r: any) => [r.employeeId, r]))
+
   const saveMutation = useMutation({
     mutationFn: (data: any) => api.post('/social/special-deduction', { ...data, month }),
     onSuccess: () => {
@@ -1129,6 +1144,23 @@ function SpecialDeductionTab({ month, setMonth }: { month: string; setMonth: (m:
     } : { children: 0, elderly: 0, housing: 0, education: 0, infant: 0, remark: '' })
   }
 
+  /** 复制上月数据到编辑表单 */
+  const copyFromPrevMonth = (empId: string) => {
+    const prev = prevRecordMap.get(empId)
+    if (prev) {
+      setEditForm({
+        children: prev.children || 0,
+        elderly: prev.elderly || 0,
+        housing: prev.housing || 0,
+        education: prev.education || 0,
+        infant: prev.infant || 0,
+        remark: prev.remark || '',
+      })
+    } else {
+      toast.info(`${prevMonth} 无该员工的扣除记录`)
+    }
+  }
+
   const calcTotal = (f: any) => (f.children || 0) + (f.elderly || 0) + (f.housing || 0) + (f.education || 0) + (f.infant || 0)
 
   return (
@@ -1177,6 +1209,7 @@ function SpecialDeductionTab({ month, setMonth }: { month: string; setMonth: (m:
                           <td className="py-1">
                             <div className="flex gap-1">
                               <Button size="sm" className="!h-7 !px-2" onClick={() => saveMutation.mutate({ employeeId: r.employeeId, ...editForm })} disabled={saveMutation.isPending}>保存</Button>
+                              <Button size="sm" variant="secondary" className="!h-7 !px-2" onClick={() => copyFromPrevMonth(r.employeeId)} disabled={!prevRecordMap.has(r.employeeId)}>复制上月</Button>
                               <Button size="sm" variant="secondary" className="!h-7 !px-2" onClick={() => { setEditing(null); setEditForm(null) }}>取消</Button>
                             </div>
                           </td>
@@ -1237,6 +1270,7 @@ function SpecialDeductionTab({ month, setMonth }: { month: string; setMonth: (m:
               </div>
               <div className="flex gap-2">
                 <Button size="sm" onClick={() => saveMutation.mutate({ employeeId: editing, ...editForm })} disabled={saveMutation.isPending}>保存</Button>
+                <Button size="sm" variant="secondary" onClick={() => copyFromPrevMonth(editing)} disabled={!prevRecordMap.has(editing)}>复制上月</Button>
                 <Button size="sm" variant="secondary" onClick={() => { setEditing(null); setEditForm(null) }}>取消</Button>
               </div>
             </div>