diff --git a/app/question_gen/distractor_selector.py b/app/question_gen/distractor_selector.py
index f09a728..5c3d1a1 100644
--- a/app/question_gen/distractor_selector.py
+++ b/app/question_gen/distractor_selector.py
@@ -188,7 +188,11 @@ async def _score_options(
     if not isinstance(scores_raw, list) or len(scores_raw) != len(options):
         msg = f"打分数量({len(scores_raw) if isinstance(scores_raw, list) else 'NA'}) != 选项数({len(options)})"
         raise ValueError(msg)
-    return [max(0.0, min(1.0, float(s))) for s in scores_raw]
+    try:
+        return [max(0.0, min(1.0, float(s))) for s in scores_raw]
+    except (TypeError, ValueError) as e:
+        msg = f"打分含非数值元素: {e}"
+        raise ValueError(msg) from e
 
 
 async def build_grounded_options(
diff --git a/tests/unit/test_distractor_selector.py b/tests/unit/test_distractor_selector.py
index 95edc3f..513c52f 100644
--- a/tests/unit/test_distractor_selector.py
+++ b/tests/unit/test_distractor_selector.py
@@ -63,6 +63,14 @@ async def test_generate_pool_degrades_on_malformed_response():
     assert out == []
 
 
+@pytest.mark.asyncio
+async def test_score_options_raises_valueerror_on_non_numeric():
+    from app.question_gen.distractor_selector import _score_options
+    vlm = _FakeVLM(['{"scores": [0.9, null, 0.5]}'])  # null 不是数值
+    with pytest.raises(ValueError):
+        await _score_options(vlm, "?", ["蒸", "炒", "煮"], _Material(), session_id="s")
+
+
 @pytest.mark.asyncio
 async def test_build_grounded_options_happy_path():
     pool = '{"distractors": ["炒", "煮", "炸", "烤"]}'