diff --git a/sanguo_factor/batch_eval.py b/sanguo_factor/batch_eval.py
index 0fb3790..8a7a110 100644
--- a/sanguo_factor/batch_eval.py
+++ b/sanguo_factor/batch_eval.py
@@ -72,7 +72,7 @@ def run_batch_eval(
     run_id = eval_store.create_run(
         eval_db, label=label, universe=universe_label,
         symbols_count=bars["vt_symbol"].n_unique(), factors_total=len(factor_names),
-        start=start, end=end, params={"limit": limit, "symbols": symbols[:20] if symbols else None},
+        start=start, end=end, params={"limit": limit, "symbols": symbols[:20] if symbols else None},  # 截断防 4400 只全量塞 JSON
     )
 
     errors: list[str] = []
@@ -115,6 +115,10 @@ def _eval_one(name: str, alpha_df: pl.DataFrame, eval_rows: pl.DataFrame,
             .sort("datetime").to_pandas().set_index("datetime")
         )
         F.index = pd.to_datetime(F.index)
+        if F.empty or len(F.index) == 0:
+            return {"factor": name, "category": factor["category"],
+                    "expression": factor["expression"],
+                    "metrics": {"error": "因子矩阵为空(join 后无评估窗行,检查 datetime dtype/窗口)"}}
         metrics = summarize_factor(F, rets[1], rets[5], rets[10])
         return {"factor": name, "category": factor["category"],
                 "expression": factor["expression"], "metrics": metrics}