A method for processing transaction information is provided according to the present invention. The method enables business vender to provide consumers with paperless transaction information, e.g. invoice information, via a route mainframe and a electronic data interchange platform. The method includes providing a mobile electronic device and establishing an information service platform to connect the electronic data interchange platform, for providing the consumers a means for payment of bills; when the cash register of the business vender receives a request of the payment of bills by using the mobile electronic device, having the card reader to access balance of the electronic purse of the mobile electronic device; judging whether the balance of the electronic purse is enough for the payment of bills, if not, prohibiting the mobile electronic device from proceeding to the payment of bills, and terminating the transaction information process; if yes, then having the mobile electronic device proceed to the payment of bills and allowing the cash register to transmit, via the route mainframe and the electronic data interchange platform, transaction information received to the information service platform for saving; and transmitting at least a part of the transaction information to the mobile electronic device by the information service platform.