diff --git a/client/src/pages/admin/FourHourExport.tsx b/client/src/pages/admin/FourHourExport.tsx
index bbec85c..78e2f4f 100644
--- a/client/src/pages/admin/FourHourExport.tsx
+++ b/client/src/pages/admin/FourHourExport.tsx
@@ -194,67 +194,42 @@ export default function FourHourExport() {
 
   const doExcel = () => {
     if (!preview) { alert('请先生成预览'); return; }
+    if (!preview.activity_matrix?.activities?.length || !preview.activity_matrix?.users?.length) {
+      alert('当前预览中无可导出的活动矩阵数据');
+      return;
+    }
     const sheets: Parameters<typeof exportToExcel>[0] = [];
-
-    const flatRows = (preview.hours || []).map((h: any, i: number) => {
-      const hoursTxt = Number(h.hours || 0).toFixed(1) + (h.truncated ? '（截断）' : '');
-      return {
-        '序号': i + 1,
-        '班级': h.class,
-        '姓名': h.name,
-        '义工号': h.volunteer_no || '-',
-        '工作组': h.group_name || '-',
-        '活动名称': h.activity_title,
-        '活动时间': String(h.activity_start_time || '').replace('T', ' ').slice(0, 16),
-        '本次计时长(小时)': hoursTxt,
-        '备注': h.remark || '-',
+    const { activities, users } = preview.activity_matrix;
+    const data = users.map((u: any) => {
+      const row: any = {
+        '部员': u.name,
+        '班级': u.class || '-',
+        '义工号': u.volunteer_no || '-',
+        '工作组': u.group_name || '-',
       };
+      for (const a of activities) {
+        const h = Number(u[String(a.id)] || 0);
+        const rmk = (u as any)?._remarks?.[String(a.id)] as string | undefined;
+        const tr = (u as any)?._truncated?.[String(a.id)] as boolean | undefined;
+        let cell = h > 0 ? h.toFixed(1) : '—';
+        if (tr) cell = cell + '（截断）';
+        if (rmk) cell = cell + '\n备注：' + rmk;
+        const colTitle = `${a.title}（${String(a.start_time || '').slice(0,10)}）`;
+        row[colTitle] = cell;
+      }
+      row['本次核销合计(h)'] = Number(u._total || 0).toFixed(1);
+      return row;
     });
-    sheets.push({ name: '总合明细（4h核销）', data: flatRows });
-
-    if (preview.user_totals?.length) {
-      sheets.push({
-        name: '部员核销汇总',
-        data: preview.user_totals.map((u: any) => ({
-          '排名': u.rank,
-          '班级': u.class,
-          '姓名': u.name,
-          '义工号': u.volunteer_no || '-',
-          '工作组': u.group_name || '-',
-          '本次核销(h)': Number(u.exported_total || 0).toFixed(1),
-          '核销后剩余未导出(h)': Number(u.unexported_remaining || 0).toFixed(1),
-        })),
-      });
-    }
-
-    if (preview.activity_matrix?.activities?.length && preview.activity_matrix?.users?.length) {
-      const { activities, users } = preview.activity_matrix;
-      const data = users.map((u: any) => {
-        const row: any = { '部员': u.name, '义工号': u.volunteer_no || '-' };
-        for (const a of activities) {
-          const h = Number(u[String(a.id)] || 0);
-          const rmk = (u as any)?._remarks?.[String(a.id)] as string | undefined;
-          const tr = (u as any)?._truncated?.[String(a.id)] as boolean | undefined;
-          let cell = h > 0 ? h.toFixed(1) : '—';
-          if (tr) cell = cell + '（截断）';
-          if (rmk) cell = cell + '\n备注：' + rmk;
-          row[a.title] = cell;
-        }
-        row['本次核销合计'] = Number(u._total || 0).toFixed(1);
-        return row;
-      });
-      const firstAct = preview.activity_matrix.activities[0];
-      sheets.push({
-        name: '活动矩阵（4h核销）',
-        data,
-        hint: firstAct ? {
-          matrixColStart: String(firstAct.title),
-          matrixColEnd: '本次核销合计',
-        } : undefined,
-      });
-    }
-
-    exportToExcel(sheets, `义工时长-四小时导出-${utc8DateStamp()}.xlsx`);
+    const firstColTitle = activities[0] ? `${activities[0].title}（${String(activities[0].start_time || '').slice(0,10)}）` : '';
+    sheets.push({
+      name: '活动矩阵总表（四小时核销）',
+      data,
+      hint: firstColTitle ? {
+        matrixColStart: firstColTitle,
+        matrixColEnd: '本次核销合计(h)',
+      } : undefined,
+    });
+    exportToExcel(sheets, `义工时长-四小时导出-活动矩阵总表-${utc8DateStamp()}.xlsx`);
   };
 
   const doImage = async () => {
@@ -275,6 +250,8 @@ export default function FourHourExport() {
               按部员维度：每位部员「尚未核销的累计义工时」≥ 4h 即列入当次导出。
               单次活动若剩余时长超过 4h，显示时自动截断为 4.0（并标注「截断」），但原始登记时长不变。
               点击「确认核销」后，本次合计小时数将写入核销记录，下次自动扣除、不会重复统计。
+              <br />
+              <span className="text-gray-600">导出 Excel 仅包含 <b className="text-primary-700">活动矩阵总表</b> 单一工作表（部员×活动，末尾含本次核销合计列）。</span>
             </p>
           </div>
         </div>
@@ -326,7 +303,7 @@ export default function FourHourExport() {
         </div>
         <div className="flex flex-col md:flex-row md:items-center md:justify-between gap-3 mt-5 pt-4 border-t border-primary-100/70">
           <div className="muted text-sm">
-            建议流程：<span className="font-semibold text-gray-700">生成预览 → 核对数据 → 导出 Excel/图片留档 → 确认核销</span>。
+            建议流程：<span className="font-semibold text-gray-700">生成预览 → 核对活动矩阵 → 导出【活动矩阵总表】Excel / 截图留档 → 确认核销</span>。
           </div>
           <div className="flex gap-2 flex-wrap justify-end">
             <Button variant="secondary" onClick={loadPreview} disabled={loading}>
diff --git a/server/src/routes/export.ts b/server/src/routes/export.ts
index c1c4a9d..10f5506 100644
--- a/server/src/routes/export.ts
+++ b/server/src/routes/export.ts
@@ -408,8 +408,10 @@ router.post('/four-hour/confirm', authMiddleware, (req: AuthRequest, res) => {
         insItem.run(exportId, it.hour_id, it.delta);
       }
     }
+    try { db.execCompat('COMMIT'); } catch (err: any) {
+      if (!/no transaction is active/i.test(String(err?.message || ''))) throw err;
+    }
     db.save();
-    db.execCompat('COMMIT');
     res.json({ ok: true, updated, skipped, total_processed: plan.length, export_id: exportId, total_applied: Number(totalApplied.toFixed(1)) });
   } catch (e: any) {
     try { db.execCompat('ROLLBACK'); } catch {}
@@ -487,8 +489,10 @@ router.post('/four-hour/void', authMiddleware, (req: AuthRequest, res) => {
       `\n[已撤回 ${new Date().toISOString().slice(0,19).replace('T',' ')}${adminUsername ? ' by '+adminUsername : ''}]`,
       exportId
     );
+    try { db.execCompat('COMMIT'); } catch (err: any) {
+      if (!/no transaction is active/i.test(String(err?.message || ''))) throw err;
+    }
     db.save();
-    db.execCompat('COMMIT');
     res.json({ ok: true, export_id: exportId, rolled, skipped, rolled_hours: Number(rolledHours.toFixed(1)) });
   } catch (e: any) {
     try { db.execCompat('ROLLBACK'); } catch {}