diff --git a/contest/models.py b/contest/models.py
index 190fce3f..8b8a2606 100644
--- a/contest/models.py
+++ b/contest/models.py
@@ -95,7 +95,7 @@ class ContestSubmission(models.Model):
     # 总的时间，用于acm 类型的，也需要保存罚时
     total_time = models.IntegerField(default=0)
     # 第一个解出此题目
-    first_achieved = models.BooleanField()
+    first_achieved = models.BooleanField(default=False)
 
     class Meta:
         db_table = "contest_submission"