Abstract: A payment method in transaction has the steps of customer providing a customer code issued by the transaction identification center to the merchant for undergoing a transaction by the mobile communication device; merchant presenting an invoicing request to the transaction identification center by means of the mobile communication device and inputting a merchant code issued by the transaction identification center, the customer code and consumed money to the transaction identification center; transaction identification center presenting a payment request to the customer with the merchant name and the consumed money for consent; the customer inputting the transaction code to show the consent of this transaction or pressing a predetermined button for cancellation; the transaction identification center confirming the input transaction code and generating an authorization code to the merchant to show the recognition of this transaction; and recording the transaction information in a financial organization for send