diff --git a/qlib/backtest/exchange.py b/qlib/backtest/exchange.py
index e2707ad39..cc88528fd 100644
--- a/qlib/backtest/exchange.py
+++ b/qlib/backtest/exchange.py
@@ -690,12 +690,14 @@ class Exchange:
                 f"Order clipped due to volume limitation: {order}, {[(vol, rule) for vol, rule in zip(vol_limit_num, vol_limit)]}"
             )
 
-    def _get_buy_amount_by_cash_limit(self, trade_price, cash):
+    def _get_buy_amount_by_cash_limit(self, trade_price, cash, cost_ratio):
         """return the real order amount after cash limit for buying.
         Parameters
         ----------
         trade_price : float
         position : cash
+        cost_ratio : float
+
         Return
         ----------
         float
@@ -704,10 +706,10 @@ class Exchange:
         max_trade_amount = 0
         if cash >= self.min_cost:
             # critical_price means the stock transaction price when the service fee is equal to min_cost.
-            critical_price = self.min_cost / self.open_cost + self.min_cost
+            critical_price = self.min_cost / cost_ratio + self.min_cost
             if cash >= critical_price:
-                # the service fee is equal to open_cost * trade_amount
-                max_trade_amount = cash / (1 + self.open_cost) / trade_price
+                # the service fee is equal to cost_ratio * trade_amount
+                max_trade_amount = cash / (1 + cost_ratio) / trade_price
             else:
                 # the service fee is equal to min_cost
                 max_trade_amount = (cash - self.min_cost) / trade_price
@@ -765,9 +767,13 @@ class Exchange:
             if position is not None:
                 cash = position.get_cash()
                 trade_val = order.deal_amount * trade_price
-                if cash < trade_val + max(trade_val * cost_ratio, self.min_cost):
+                if cash < max(trade_val * cost_ratio, self.min_cost):
+                    # cash cannot cover cost
+                    order.deal_amount = 0
+                    self.logger.debug(f"Order clipped due to cost higher than cash: {order}")
+                elif cash < trade_val + max(trade_val * cost_ratio, self.min_cost):
                     # The money is not enough
-                    max_buy_amount = self._get_buy_amount_by_cash_limit(trade_price, cash)
+                    max_buy_amount = self._get_buy_amount_by_cash_limit(trade_price, cash, cost_ratio)
                     order.deal_amount = self.round_amount_by_trade_unit(
                         min(max_buy_amount, order.deal_amount), order.factor
                     )