diff --git a/webapp/services/BattleDataService.php b/webapp/services/BattleDataService.php
index 08ab7284..7ff5c022 100644
--- a/webapp/services/BattleDataService.php
+++ b/webapp/services/BattleDataService.php
@@ -470,6 +470,18 @@ class BattleDataService extends BaseService {
         }
 
         $onlineNum = $this->getOnlineNumber();
+
+        $heroProbability = min($heroFragment[$now].total / $onlineNum * 5 * ($instanceRankRate + $bossReward*0.2) * pow(2, $todayPveBattleTimes - $todayPveGetFragmentNum -1), 1);
+        $gunProbability = min($gunFragment[$now].total / $onlineNum * $dropRate * ($instanceRankRate + $bossReward*0.2) * pow(2, $todayPveBattleTimes - $todayPveGetFragmentNum -1), 1);
+
+        $heroProbability = max($heroProbability, 0);
+        $gunProbability = max($gunProbability, 0);
+        $emptyProbability = max(1 - $heroProbability - $gunProbability, 0);
+
+        $dropIdx = $this->randWeight(array($heroProbability, $gunProbability, $emptyProbability));
+        if ($dropIdx < 0 || $dropIdx == 2) {
+            return;
+        }
     }
 
     private function rewardFragmentPve()