diff --git a/extend/fast/Random.php b/extend/fast/Random.php
index 7edade5..1e25a1d 100644
--- a/extend/fast/Random.php
+++ b/extend/fast/Random.php
@@ -42,7 +42,7 @@ class Random
     }
 
     /**
-     * 数字和字母组合的随机字符串
+     * 生成指定长度的无0随机数字
      *
      * @param int $len 长度
      * @return string