diff --git a/System/Abstracts/Crontab.php b/System/Abstracts/Crontab.php
index 7ee5e434..1f24c337 100644
--- a/System/Abstracts/Crontab.php
+++ b/System/Abstracts/Crontab.php
@@ -58,7 +58,7 @@ class Crontab extends Component
     public function clearAll()
     {
         $redis = Snowflake::app()->getRedis();
-        $data = $redis->zRange(self::CRONTAB_KEY, 0, -1);
+        $data = $redis->zRange(self::CRONTAB_KEY, '0', '-1');
         $redis->del(self::CRONTAB_KEY);
         foreach ($data as $datum) {
             $redis->del('crontab:' . md5($datum));