diff --git a/submission/api.py b/submission/api.py
index fe1a9d1..150eed0 100644
--- a/submission/api.py
+++ b/submission/api.py
@@ -5,6 +5,7 @@ from ninja.errors import HttpError
 from ninja.pagination import paginate
 from django.shortcuts import get_object_or_404
 from django.contrib.auth.decorators import login_required
+from django.db.models import OuterRef, Subquery, IntegerField
 
 
 from .schemas import (
@@ -55,19 +56,20 @@ def list_submissions(request, filters: SubmissionFilter = Query(...)):
     if filters.username:
         submissions = submissions.filter(user__username__icontains=filters.username)
 
-    # 获取所有提交
-    submissions = submissions.prefetch_related("ratings")
-    
-    # 获取当前用户的评分
-    user_ratings = {
-        rating.submission_id: rating.score
-        for rating in Rating.objects.filter(
-            user=request.user,
-            submission__in=submissions
-        )
-    }
+    user_rating_subquery = Subquery(
+        Rating.objects.filter(user=request.user, submission=OuterRef("pk")).values(
+            "score"
+        )[:1],
+        output_field=IntegerField(),
+    )
+    submissions = submissions.annotate(my_score=user_rating_subquery)
 
-    return [SubmissionOut.list(submission, user_ratings) for submission in submissions]
+    def get_submission_data(submission):
+        """从 submission 对象构建 SubmissionOut 数据"""
+        my_score = getattr(submission, "my_score", None) or 0
+        return SubmissionOut.list(submission, {submission.id: my_score})
+
+    return [get_submission_data(submission) for submission in submissions]
 
 
 @router.get("/{submission_id}", response=SubmissionOut)