diff --git a/app/common/controller/UsedCarController.php b/app/common/controller/UsedCarController.php
index 1d34a63..3e4955d 100644
--- a/app/common/controller/UsedCarController.php
+++ b/app/common/controller/UsedCarController.php
@@ -395,9 +395,16 @@ class UsedCarController extends BaseController
             if (!file_exists($publicFile)) {
                 copy($filePath, $publicFile);
             }
+            
+            // 从连接中获取协议（最可靠）
+            $connection = $request->connection;
+            $protocol = 'https';
+            if ($connection && property_exists($connection, 'transport')) {
+                $protocol = $connection->transport === 'ssl' ? 'https' : 'http';
+            }
 
             // 返回访问地址
-            $baseUrl = 'http://' . request()->header('host');
+            $baseUrl = $protocol.'://' . request()->header('host');
             $url = $baseUrl . '/pdf/' . $raw['pdf_src'];
 
             return $this->success([