diff --git a/backend/api/routes/account.py b/backend/api/routes/account.py
index 0b18b00..67d1400 100644
--- a/backend/api/routes/account.py
+++ b/backend/api/routes/account.py
@@ -1623,8 +1623,8 @@ async def sync_positions(
             if binance_symbols:
                 logger.info(f"  持仓列表: {', '.join(binance_symbols)}")
             
-            # 2. 获取数据库中状态为open的交易记录
-            db_open_trades = Trade.get_all(status='open', account_id=account_id)
+            # 2. 获取数据库中状态为open的交易记录（限制条数防内存暴增）
+            db_open_trades = Trade.get_all(status='open', account_id=account_id, limit=500)
             db_open_symbols = {t['symbol'] for t in db_open_trades}
             logger.info(f"数据库open状态: {len(db_open_symbols)} 个")
             if db_open_symbols:
diff --git a/backend/api/routes/stats.py b/backend/api/routes/stats.py
index a2ffd98..1e8cc66 100644
--- a/backend/api/routes/stats.py
+++ b/backend/api/routes/stats.py
@@ -82,9 +82,16 @@ async def get_performance_stats(
         # 账户快照
         snapshots = AccountSnapshot.get_recent(days, account_id=account_id)
         
-        # 交易统计
-        start_date = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
-        trades = Trade.get_all(start_date=start_date, account_id=account_id)
+        # 交易统计（时间范围 + limit 防内存暴增）
+        start_ts = int((datetime.now() - timedelta(days=days)).timestamp())
+        end_ts = int(datetime.now().timestamp())
+        trades = Trade.get_all(
+            start_timestamp=start_ts,
+            end_timestamp=end_ts,
+            account_id=account_id,
+            time_filter="exit",
+            limit=10000,
+        )
         
         return {
             "snapshots": snapshots,
@@ -162,7 +169,7 @@ async def get_dashboard_data(account_id: int = Depends(get_account_id)):
                 logger.warning(f"获取币安实时持仓失败，回退到数据库列表: {fetch_err}")
                 open_trades = []
             if not open_trades:
-                db_trades = Trade.get_all(status='open', account_id=account_id)
+                db_trades = Trade.get_all(status='open', account_id=account_id, limit=500)
                 for trade in db_trades:
                     entry_value_usdt = float(trade.get('quantity', 0)) * float(trade.get('entry_price', 0))
                     leverage = float(trade.get('leverage', 1))
diff --git a/backend/api/routes/trades.py b/backend/api/routes/trades.py
index 2044299..addbf26 100644
--- a/backend/api/routes/trades.py
+++ b/backend/api/routes/trades.py
@@ -773,6 +773,7 @@ async def sync_trades_from_binance(
                                 end_timestamp=time_window_end,
                                 time_filter="entry",
                                 reconciled_only=False,
+                                limit=500,
                             )
                             trades_no_entry_id = [
                                 t for t in trades_in_window
@@ -871,6 +872,7 @@ async def verify_trades_against_binance(
         account_id=account_id,
         start_timestamp=start_ts,
         end_timestamp=end_ts,
+        limit=10000,
     )
     # 只校验「可对账」记录：有 entry_order_id；若已平仓则还须有 exit_order_id
     def _has_entry(eid):
diff --git a/backend/database/models.py b/backend/database/models.py
index d9ad695..7e5f512 100644
--- a/backend/database/models.py
+++ b/backend/database/models.py
@@ -1134,10 +1134,10 @@ class Trade:
             query += " ORDER BY " + time_col + " DESC, id DESC"
         else:
             query += " ORDER BY COALESCE(exit_time, entry_time) DESC, id DESC"
-        # 未传 limit 时使用默认上限，防止全表加载导致内存暴增
+        # 未传 limit 时使用默认上限，防止全表加载导致内存暴增（2 CPU 4G 场景）
         _limit = limit
         if _limit is None or _limit <= 0:
-            _limit = 20000
+            _limit = 10000
         query += " LIMIT %s"
         params.append(int(_limit))
         logger.debug(f"查询交易记录: time_filter={time_filter}, limit={_limit}, reconciled_only={reconciled_only}, include_sync={include_sync}")