diff --git a/app/common/service/UsedCarDetailService.php b/app/common/service/UsedCarDetailService.php
index 5c533ff..0d43e55 100644
--- a/app/common/service/UsedCarDetailService.php
+++ b/app/common/service/UsedCarDetailService.php
@@ -464,7 +464,9 @@ class UsedCarDetailService
             ->get()
             ->map(function ($item) {
                 if(!is_numeric($item->created_at)){
-                    $item->created_at = strtotime($item->created_at);
+                    $created_at = $item->created_at->timestamp;
+                }else{
+                    $created_at = $item->created_at;
                 }
                 return [
                     'id' => $item->id,
@@ -474,7 +476,7 @@ class UsedCarDetailService
                     'before_status' => $item->before_status,
                     'after_status' => $item->after_status,
                     'auditor_name' => $item->auditor->name ?? '',
-                    'created_at' => date('Y-m-d H:i:s', $item->created_at),
+                    'created_at' => date('Y-m-d H:i:s', $created_at),
                 ];
             });
     }