diff --git a/Dockerfile b/Dockerfile
index f38f18f..79f851f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -16,6 +16,10 @@ FROM node:20-alpine AS runtime
 WORKDIR /app
 ENV NODE_ENV=production
 ENV PORT=3000
+ENV TZ=Asia/Shanghai
+RUN apk add --no-cache tzdata \
+  && ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime \
+  && echo "Asia/Shanghai" > /etc/timezone
 
 COPY server/package.json server/package-lock.json* ./
 RUN npm install --omit=dev --no-audit --no-fund
diff --git a/client/src/pages/admin/Activities.tsx b/client/src/pages/admin/Activities.tsx
index 6d66d61..cf044a5 100644
--- a/client/src/pages/admin/Activities.tsx
+++ b/client/src/pages/admin/Activities.tsx
@@ -6,18 +6,13 @@ import Input from '../../components/Input';
 import Select from '../../components/Select';
 import Textarea from '../../components/Textarea';
 import { activitiesApi, groupsApi, errMsg } from '../../api';
-import { formatDateRange } from '../../utils/export';
+import { formatDateRange, utc8Now, utc8Input } from '../../utils/export';
 import type { ActivityItem, WorkGroup } from '../../types';
 import { IconCalendar, IconPlus, IconTrash, IconEdit } from '../../components/Icons';
 
 type Form = { title: string; content: string; start_time: string; end_time: string; groups: number[] };
 const emptyForm: Form = { title: '', content: '', start_time: '', end_time: '', groups: [] };
 
-function toLocalInput(d: Date) {
-  const pad = (n: number) => String(n).padStart(2, '0');
-  return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())}T${pad(d.getHours())}:${pad(d.getMinutes())}`;
-}
-
 export default function Activities() {
   const [list, setList] = useState<ActivityItem[]>([]);
   const [groups, setGroups] = useState<WorkGroup[]>([]);
@@ -43,9 +38,9 @@ export default function Activities() {
   useEffect(() => { load(); }, []);
 
   const openNew = () => {
-    const now = new Date();
+    const now = utc8Now();
     const end = new Date(now.getTime() + 2 * 3600 * 1000);
-    setForm({ ...emptyForm, start_time: toLocalInput(now), end_time: toLocalInput(end) });
+    setForm({ ...emptyForm, start_time: utc8Input(now), end_time: utc8Input(end) });
     setEditId(null);
     setError('');
     setModalOpen(true);
diff --git a/client/src/pages/admin/Export.tsx b/client/src/pages/admin/Export.tsx
index c207779..19b767e 100644
--- a/client/src/pages/admin/Export.tsx
+++ b/client/src/pages/admin/Export.tsx
@@ -1,7 +1,7 @@
 import { ReactNode, useRef, useState } from 'react';
 import Button from '../../components/Button';
 import { exportApi, errMsg } from '../../api';
-import { exportToExcel, exportTableToImage, formatDateRange } from '../../utils/export';
+import { exportToExcel, exportTableToImage, formatDateRange, utc8DateStamp, utc8DateTimeStamp } from '../../utils/export';
 import type { ExportResult } from '../../types';
 import {
   IconExport,
@@ -226,12 +226,12 @@ export default function Export() {
       });
       sheets.push({ name: '活动时长总表(矩阵)', data });
     }
-    exportToExcel(sheets, `义工数据-全部导出-${new Date().toISOString().slice(0, 10)}.xlsx`);
+    exportToExcel(sheets, `义工数据-全部导出-${utc8DateStamp()}.xlsx`);
   };
 
   const doImage = async () => {
     if (!previewRef.current) return;
-    await exportTableToImage(previewRef.current, `义工数据-全部导出-${new Date().toISOString().slice(0, 10)}.png`);
+    await exportTableToImage(previewRef.current, `义工数据-全部导出-${utc8DateStamp()}.png`);
   };
 
   return (
@@ -315,7 +315,7 @@ export default function Export() {
         <div ref={previewRef} className="card bg-white p-3 md:p-6 space-y-8">
           <div className="border-b border-gray-200 pb-4 text-center">
             <div className="text-xl md:text-2xl font-semibold tracking-tight text-gray-800">宣传部义工时长记录系统 · 数据导出报告</div>
-            <div className="muted mt-1.5">义工数据汇总导出 | 生成时间：{new Date().toLocaleString('zh-CN')}</div>
+            <div className="muted mt-1.5">义工数据汇总导出 | 生成时间：{utc8DateTimeStamp()}</div>
           </div>
 
           {preview.users?.length ? (
diff --git a/client/src/pages/admin/Hours.tsx b/client/src/pages/admin/Hours.tsx
index 84b5142..168a5f9 100644
--- a/client/src/pages/admin/Hours.tsx
+++ b/client/src/pages/admin/Hours.tsx
@@ -3,7 +3,7 @@ import Button from '../../components/Button';
 import Select from '../../components/Select';
 import Input from '../../components/Input';
 import { activitiesApi, hoursApi, errMsg } from '../../api';
-import { exportToExcel, exportTableToImage, formatDateRange } from '../../utils/export';
+import { exportToExcel, exportTableToImage, formatDateRange, utc8DateStamp } from '../../utils/export';
 import type { ActivityItem, HoursRow, Participant, HoursActivityResult } from '../../types';
 import { IconClock, IconFileExcel, IconFileImage } from '../../components/Icons';
 
@@ -96,13 +96,13 @@ export default function Hours() {
       '备注': p.remark || '—',
     }));
     const meta = [{ '活动名称': title, '活动时间': formatDateRange(activityInfo?.start_time || '', activityInfo?.end_time || ''), '登记人数': summary.people, '总时长(小时)': summary.hours.toFixed(2) }];
-    exportToExcel([{ name: '汇总', data: meta }, { name: '时长明细', data }], `义工时长-${title}-${new Date().toISOString().slice(0,10)}.xlsx`);
+    exportToExcel([{ name: '汇总', data: meta }, { name: '时长明细', data }], `义工时长-${title}-${utc8DateStamp()}.xlsx`);
   };
 
   const doImageExport = async () => {
     if (!tableRef.current) return;
     const title = activityInfo?.title || '活动';
-    await exportTableToImage(tableRef.current, `义工时长-${title}-${new Date().toISOString().slice(0,10)}.png`);
+    await exportTableToImage(tableRef.current, `义工时长-${title}-${utc8DateStamp()}.png`);
   };
 
   return (
diff --git a/client/src/utils/export.ts b/client/src/utils/export.ts
index 8818a9b..4764d90 100644
--- a/client/src/utils/export.ts
+++ b/client/src/utils/export.ts
@@ -1,6 +1,30 @@
 import * as XLSX from 'xlsx';
 import html2canvas from 'html2canvas';
 
+const TZ_OFFSET_HOURS = 8;
+
+function pad2(n: number): string {
+  return String(Math.floor(Math.max(0, n))).padStart(2, '0');
+}
+
+export function utc8Now(): Date {
+  const d = new Date();
+  const utcMs = d.getTime() + d.getTimezoneOffset() * 60000;
+  return new Date(utcMs + TZ_OFFSET_HOURS * 3600000);
+}
+
+export function utc8Input(d: Date = utc8Now()): string {
+  return `${d.getFullYear()}-${pad2(d.getMonth() + 1)}-${pad2(d.getDate())}T${pad2(d.getHours())}:${pad2(d.getMinutes())}`;
+}
+
+export function utc8DateStamp(d: Date = utc8Now()): string {
+  return `${d.getFullYear()}-${pad2(d.getMonth() + 1)}-${pad2(d.getDate())}`;
+}
+
+export function utc8DateTimeStamp(d: Date = utc8Now()): string {
+  return `${utc8DateStamp(d)} ${pad2(d.getHours())}:${pad2(d.getMinutes())}:${pad2(d.getSeconds())}`;
+}
+
 function downloadBlob(blob: Blob, filename: string) {
   const url = URL.createObjectURL(blob);
   const a = document.createElement('a');
@@ -42,3 +66,11 @@ export function formatDateRange(s: string, e: string) {
   const b = e?.replace('T', ' ')?.slice(0, 16);
   return `${a || ''} ~ ${b || ''}`;
 }
+
+export function formatCnDateTime(s?: string | null, withSeconds = false): string {
+  if (!s) return '';
+  const str = String(s).replace('T', ' ');
+  const max = withSeconds ? 19 : 16;
+  return str.slice(0, max);
+}
+
diff --git a/docker-compose.yml b/docker-compose.yml
index 9b92127..0c9bca0 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -8,7 +8,9 @@ services:
       - "3000:3000"
     volumes:
       - ./server/data:/app/server/data
+      - /etc/localtime:/etc/localtime:ro
     environment:
       - NODE_ENV=production
       - PORT=3000
+      - TZ=Asia/Shanghai
       - JWT_SECRET=${JWT_SECRET:-volunteer-manage-secret-key-2026}
diff --git a/server/src/db/schema.sql b/server/src/db/schema.sql
index dc6c559..433a71f 100644
--- a/server/src/db/schema.sql
+++ b/server/src/db/schema.sql
@@ -27,7 +27,7 @@ CREATE TABLE IF NOT EXISTS activities (
   content TEXT,
   start_time TEXT NOT NULL,
   end_time TEXT NOT NULL,
-  created_at TEXT NOT NULL DEFAULT (datetime('now','localtime'))
+  created_at TEXT NOT NULL DEFAULT (datetime('now','+8 hours'))
 );
 
 CREATE TABLE IF NOT EXISTS activity_groups (
@@ -44,7 +44,7 @@ CREATE TABLE IF NOT EXISTS hours (
   user_id INTEGER NOT NULL,
   hours REAL NOT NULL DEFAULT 0,
   remark TEXT,
-  created_at TEXT NOT NULL DEFAULT (datetime('now','localtime')),
+  created_at TEXT NOT NULL DEFAULT (datetime('now','+8 hours')),
   FOREIGN KEY (activity_id) REFERENCES activities(id) ON DELETE CASCADE,
   FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
   UNIQUE(activity_id, user_id)
@@ -54,5 +54,5 @@ CREATE TABLE IF NOT EXISTS admins (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
   username TEXT NOT NULL UNIQUE,
   password_hash TEXT NOT NULL,
-  created_at TEXT NOT NULL DEFAULT (datetime('now','localtime'))
+  created_at TEXT NOT NULL DEFAULT (datetime('now','+8 hours'))
 );
diff --git a/server/src/index.ts b/server/src/index.ts
index e18fea7..37c89ca 100644
--- a/server/src/index.ts
+++ b/server/src/index.ts
@@ -10,6 +10,8 @@ import activitiesRoutes from './routes/activities';
 import hoursRoutes from './routes/hours';
 import exportRoutes from './routes/export';
 
+process.env.TZ = 'Asia/Shanghai';
+
 async function bootstrap() {
   await initDb();
   const app = express();