diff --git a/webapp/models/HashRate.php b/webapp/models/HashRate.php
index ca34c85b..61acb1dc 100644
--- a/webapp/models/HashRate.php
+++ b/webapp/models/HashRate.php
@@ -129,6 +129,24 @@ class HashRate  extends BaseModel
         return $myHashRate;
     }
 
+    public static function decMyCurrentHashRate($val){
+        $val = intval($val);
+        $currentPeriod = myself()->_callMtStatic('AchievementsCycle', 'getCurrentPeriod');
+        if ($currentPeriod) {
+            SqlHelper::update(
+                myself()->_getSelfMysql(),
+                't_hash_rate_reward',
+                array(
+                    'account_id' => myself()->_getAccountId(),
+                    'period' => $currentPeriod['id'],
+                    'reward' => function () use($val) {
+                        return "GREATEST(0, reward - ${val})";
+                    },
+                )
+            );
+        }
+    }
+
     public static function getTotalByAccount($accountId,$period){
         $row = SqlHelper::ormSelectOne(
             myself()->_getSelfMysql(),