diff --git a/backend/cmd/server/main.go b/backend/cmd/server/main.go
index f1e3a71..557b73c 100644
--- a/backend/cmd/server/main.go
+++ b/backend/cmd/server/main.go
@@ -99,7 +99,8 @@ func main() {
 		f.BindRoute("POST", "/mapi.php", service.PayMapiHandler(st, up)),
 		f.BindRoute("GET", "/api.php", service.PayApiHandler(st)),
 		f.BindRoute("POST", "/api.php", service.PayApiHandler(st)),
-		// submit.php 直出收银台页的状态轮询（经代理走 /api 前缀，直连后端也兼容）
+		// 收银台页（submit.php 的 302 落点）+ 页内状态轮询（经代理走 /api 前缀，直连后端也兼容）
+		f.BindRoute("GET", "/cashier.php", service.PayCashierPageHandler(st)),
 		f.BindRoute("GET", "/cashier-status", service.PayCashierStatusHandler(st)),
 		f.BindRoute("GET", "/api/cashier-status", service.PayCashierStatusHandler(st)),
 		f.BindRoute("GET", "/healthz", func(c *fun.RouteCtx) error {
diff --git a/backend/internal/service/cashier_page.go b/backend/internal/service/cashier_page.go
index 5d289e5..19a4719 100644
--- a/backend/internal/service/cashier_page.go
+++ b/backend/internal/service/cashier_page.go
@@ -165,6 +165,19 @@ func renderCashier(c *fun.RouteCtx, o db.PayOrder) error {
 	return nil
 }
 
+// PayCashierPageHandler GET /cashier.php?trade_no=：收银台页渲染
+// （submit.php 302 落点，trade_no 不可枚举即凭证；重复访问按订单当前状态渲染）。
+func PayCashierPageHandler(st *store.Store) fun.RouteHandler {
+	return func(c *fun.RouteCtx) error {
+		o, err := st.Q().GetPayOrderByTradeNo(context.Background(), strings.TrimSpace(c.Param("trade_no")))
+		if err != nil {
+			return epayJSON(c, map[string]any{"code": -1, "msg": "订单不存在"})
+		}
+		lazyCloseExpired(st, &o)
+		return renderCashier(c, o)
+	}
+}
+
 // PayCashierStatusHandler GET /cashier-status?trade_no=：收银台页轮询
 // （公开接口，trade_no 不可枚举即凭证；前端经 /api 前缀代理访问）。
 func PayCashierStatusHandler(st *store.Store) fun.RouteHandler {
diff --git a/backend/internal/service/pay_routes.go b/backend/internal/service/pay_routes.go
index 2e22a1b..85a64fe 100644
--- a/backend/internal/service/pay_routes.go
+++ b/backend/internal/service/pay_routes.go
@@ -12,18 +12,15 @@ import (
 	"github.com/cyi-cc/cyi-box/backend/internal/store"
 )
 
-// paySubmitHandler GET/POST /submit.php：验签建单后直接渲染收银台页（无跳转）。
+// paySubmitHandler GET/POST /submit.php：验签建单后 302 到收银台页（PRG，刷新安全）。
 func PaySubmitHandler(st *store.Store, up *payx.Client) fun.RouteHandler {
 	return func(c *fun.RouteCtx) error {
 		order, err := epayCreateOrder(c, st, up)
 		if err != nil {
 			return epayFail(c, err)
 		}
-		o, err := st.Q().GetPayOrderByTradeNo(context.Background(), order.TradeNo)
-		if err != nil {
-			return epayFail(c, err)
-		}
-		return renderCashier(c, o)
+		c.RequestCtx.Redirect("/cashier.php?trade_no="+order.TradeNo, 302)
+		return nil
 	}
 }
 
diff --git a/docker/nginx.conf b/docker/nginx.conf
index 081a966..885d7a6 100644
--- a/docker/nginx.conf
+++ b/docker/nginx.conf
@@ -62,7 +62,7 @@ server {
         proxy_read_timeout 3600s;
     }
 
-    location ~ ^/(submit|mapi|api)\.php$ {
+    location ~ ^/(submit|mapi|api|cashier)\.php$ {
         proxy_pass http://127.0.0.1:8891;
         proxy_http_version 1.1;
         proxy_set_header Host $host;