diff --git a/deploy_update.sh b/deploy_update.sh
index 6b9f2de..5ad6b03 100644
--- a/deploy_update.sh
+++ b/deploy_update.sh
@@ -42,6 +42,20 @@ if [ ! -f "vendor/autoload.php" ]; then
 fi
 echo -e "${GREEN}✅ 依赖安装成功且文件存在。${NC}"
 
+# 关键 Composer polyfill 文件检查：若 vendor 目录不完整，Laravel 接口会返回 PHP Warning HTML，前端会误判为 JSON 解析失败
+if [ ! -f "vendor/symfony/polyfill-mbstring/bootstrap.php" ]; then
+    echo -e "${RED}========================================${NC}"
+    echo -e "${RED}  ❌ 致命错误：Composer vendor 不完整！ ${NC}"
+    echo -e "${RED}  缺少 vendor/symfony/polyfill-mbstring/bootstrap.php。 ${NC}"
+    echo -e "${RED}  请删除线上 vendor 后重新执行 composer install。 ${NC}"
+    echo -e "${RED}========================================${NC}"
+    exit 1
+fi
+
+# 重新生成生产环境 autoload，避免 autoload_files.php 指向已缺失的旧文件
+composer dump-autoload --no-dev --optimize --classmap-authoritative --no-interaction
+if [ $? -ne 0 ]; then echo -e "${RED}❌ Composer autoload 重建失败${NC}"; exit 1; fi
+
 # 3. 前端构建
 echo -e "${YELLOW}[3/7] 前端构建 (npm run build)...${NC}"
 npm run build
@@ -73,4 +87,4 @@ chmod -R 775 storage bootstrap/cache
 
 echo -e "${GREEN}========================================${NC}"
 echo -e "${GREEN}  🎉 更新成功！网站已恢复。 ${NC}"
-echo -e "${GREEN}========================================${NC}"
\ No newline at end of file
+echo -e "${GREEN}========================================${NC}"