diff --git a/library/think/Request.php b/library/think/Request.php
index b41b135a..f72d6bb5 100644
--- a/library/think/Request.php
+++ b/library/think/Request.php
@@ -984,7 +984,7 @@ class Request
                         $value = $default;
                         break;
                     }
-                } else {
+                } elseif (!empty($filter)) {
                     // filter函数不存在时, 则使用filter_var进行过滤
                     // filter为非整形值时, 调用filter_id取得过滤id
                     $value = filter_var($value, is_int($filter) ? $filter : filter_id($filter));