Hello, the market order cannot be cancelled, because neither of the two market orders provided by the trading rules can be left in the trading system. If there is a balance after the transaction, the first order will be cancelled automatically immediately, and investors do not need to cancel it themselves; If the balance of the second market order remains after the transaction, it will be automatically converted into a limit order immediately, which fully conforms to the provisions of the limit order. The converted limit order can be cancelled, but it can no longer be called a market order.