diff --git a/application/api/model/Topic.php b/application/api/model/Topic.php
index cce1b47..a29677b 100644
--- a/application/api/model/Topic.php
+++ b/application/api/model/Topic.php
@@ -44,7 +44,7 @@ class Topic extends Model
         if($list){
             foreach ($list as &$item){
                 $item['content'] = $this->where(['id'=>$item['topic_id']])->value('content');
-                $item['pic'] = $this->where(['id'=>$item['topic_id']])->value('pic');
+                $item['pic'] = $this->where(['id'=>$item['topic_id']])->value('pic') ?? get_system_config_value('web_site').'/data/avatar/head_pic.png';;
                 $item['title'] = $this->where(['id'=>$item['topic_id']])->value('title');
             }
         }