diff --git a/lib/base/dao/dao.class.php b/lib/base/dao/dao.class.php
index 196640385f..3868b84645 100644
--- a/lib/base/dao/dao.class.php
+++ b/lib/base/dao/dao.class.php
@@ -1159,7 +1159,7 @@ class baseDAO
          * 如果没数据中没有该字段，直接返回。
          * If no this field in the data, return.
          **/
-        if(!isset($this->sqlobj->data->$fieldName)) return $this;
+        if(!is_null($this->sqlobj->data->$fieldName) && !isset($this->sqlobj->data->$fieldName)) return $this;
 
         /* 设置字段值。 */
         /* Set the field label and value. */