diff --git a/yunke-server/app/scraper/media.py b/yunke-server/app/scraper/media.py
index 6c0c727..ba83044 100644
--- a/yunke-server/app/scraper/media.py
+++ b/yunke-server/app/scraper/media.py
@@ -478,7 +478,13 @@ async def download_message_images(
             .limit(batch_size)
         )
         if tried:
-            stmt = stmt.where(Message.msg_id.not_in(tried))
+            # 分片进 NOT IN —— 单次塞全部 tried(3万+)会超 SQLite 变量上限
+            # (默认 32766/999),2026-08-20 实测 42k 后崩;每次最多 500 个。
+            tried_list = list(tried)
+            conds = []
+            for i in range(0, len(tried_list), 500):
+                conds.append(Message.msg_id.not_in(tried_list[i:i + 500]))
+            stmt = stmt.where(sa.and_(*conds))
         rows = (await session.execute(stmt)).all()
         if not rows:
             break