diff --git a/src/lib/a5/data.test.ts b/src/lib/a5/data.test.ts
index 6edc591..e04aecf 100644
--- a/src/lib/a5/data.test.ts
+++ b/src/lib/a5/data.test.ts
@@ -15,6 +15,12 @@ describe('A5 launch', () => {
   })
 })
 describe('A5 responses', () => {
+  it('uses the backend id as the order number, independently of payment identifiers', () => {
+    expect(adaptA5Order({ id: 42, order_id: 'legacy', transaction_id: 'payment-123', out_trade_no: 'merchant-456' }))
+      .toMatchObject({ order_id: '42', transaction_id: 'payment-123', out_trade_no: 'merchant-456' })
+    expect(adaptA5Order({ id: 43 }).order_id).toBe('43')
+    expect(adaptA5Order({ transaction_id: 'payment-only' }).order_id).toBe('')
+  })
   it('accepts numeric or string success codes, rejects failed HTTP and business responses', () => {
     expect(unwrapA5Response(200, '{"code":"0","data":[]}').data).toEqual([])
     expect(() => unwrapA5Response(404, { code: 0 })).toThrow()
diff --git a/src/pages/complaint/index.tsx b/src/pages/complaint/index.tsx
index 702d65e..47929d7 100644
--- a/src/pages/complaint/index.tsx
+++ b/src/pages/complaint/index.tsx
@@ -132,8 +132,8 @@ export default function ComplaintPage ({ services }: { services?: ComplaintServi
         </View>
         <View className='complaint-hero__meta'>
           <View className='complaint-hero__meta-row'>
-            <Text className='complaint-hero__meta-label'>交易ID</Text>
-            <Text className='complaint-hero__meta-value'>{order?.out_trade_no || '-'}</Text>
+            <Text className='complaint-hero__meta-label'>{services ? '订单编号' : '交易ID'}</Text>
+            <Text className='complaint-hero__meta-value'>{(services ? order?.order_id : order?.out_trade_no) || '-'}</Text>
           </View>
           <View className='complaint-hero__meta-row'>
             <Text className='complaint-hero__meta-label'>交易时间</Text>
diff --git a/src/pages/index/index.tsx b/src/pages/index/index.tsx
index 48c63db..18429c0 100644
--- a/src/pages/index/index.tsx
+++ b/src/pages/index/index.tsx
@@ -179,8 +179,9 @@ export default function Index ({ a5 = false }: { a5?: boolean }) {
               a5={a5}
               order={order}
               onCopy={() => {
-                if (!order.transaction_id) return
-                Taro.setClipboardData({ data: String(order.transaction_id) })
+                const number = a5 ? order.order_id : order.transaction_id
+                if (!number) return
+                Taro.setClipboardData({ data: String(number) })
               }}
               onViewDetail={() => setDetailOrder(order)}
               onResubmit={() => openOrderPage('/pages/resubmit/index', order)}
@@ -226,6 +227,7 @@ function OrderCard ({
   onResubmit: () => void
   onComplaint: () => void
 }) {
+  const number = a5 ? order.order_id : order.transaction_id
   const status = (a5 && A5_STATUSES[order.process_status]) || getStatusMeta(order.process_status, order.process_status_name)
   const actions = a5 ? { complaint: true, submit: true, detail: order.process_status === '2' } : getOrderCardActions(order)
 
@@ -242,9 +244,9 @@ function OrderCard ({
       <InfoLine label='订单时间：' value={order.create_time || order.pay_time || '-'} />
 
       <View className='order-card__row'>
-        <Text className='order-card__label'>交易单号：</Text>
-        <Text className='order-card__value order-card__value--id'>{order.transaction_id || '-'}</Text>
-        {order.transaction_id ? (
+        <Text className='order-card__label'>{a5 ? '订单编号：' : '交易单号：'}</Text>
+        <Text className='order-card__value order-card__value--id'>{number || '-'}</Text>
+        {number ? (
           <Image className='order-card__copy' src={COPY_ICON} onClick={onCopy} />
         ) : null}
       </View>