A mobile transaction method to be implemented using a portable electronic device for processing a transaction through an electronic transaction platform, the portable electronic device being removably coupled to a payment card that stores payment account information, the portable electronic device including a processor and a memory card interface that is coupled to the processor and that is operable to connect to the payment card, the payment card including a smart chip and a controller for the smart chip, the method including the following steps of: A) configuring the portable electronic device to generate transaction information related to the transaction; B) configuring the portable electronic device to obtain the payment account information from the payment card; C) configuring the portable electronic device to establish a session with the electronic transaction platform, to receive parameters, variables and data used in the session from the electronic transaction platform, and to communicate with the electronic transaction platform according to the session; and D) configuring the portable electronic device to collaborate with the electronic transaction platform to process payment for the transaction according to the transaction information generated in step A) and the payment account information obtained in step B); characterized in that step D) includes the following sub-steps of: D1) configuring the processor of the portable electronic device to transmit an authentication request to the electronic transaction platform, so that the electronic transaction platform is operable to provide authentication information to the portable electronic device in response to receipt of the authentication request from the portable electronic device, the portable electronic device and the electronic transaction platform being configured to identify the transaction with each other according to the authentication information; D2) configuring the processor of the portable electronic device to cooperate with the controller of the payment card to transmit the authentication information and the payment amount to the smart chip through the memory card interface and for generating a transaction authentication code by the controller; and D3) configuring the processor of the portable electronic device to obtain the transaction authentication code from the smart chip through the memory card interface. A) configuring the portable electronic device to generate transaction information related to the transaction; B) configuring the portable electronic device to obtain the payment account information from the payment card; C) configuring the portable electronic device to establish a session with the electronic transaction platform, to receive parameters, variables and data used in the session from the electronic transaction platform, and to communicate with the electronic transaction platform according to the session; and D) configuring the portable electronic device to collaborate with the electronic transaction platform to process payment for the transaction according to the transaction information generated in step A) and the payment account information obtained in step B); D1) configuring the processor of the portable electronic device to transmit an authentication request to the electronic transaction platform, so that the electronic transaction platform is operable to provide authentication information to the portable electronic device in response to receipt of the authentication request from the portable electronic device, the portable electronic device and the electronic transaction platform being configured to identify the transaction with each other according to the authentication information; D2) configuring the processor of the portable electronic device to cooperate with the controller of the payment card to transmit the authentication information and the payment amount to the smart chip through the memory card interface and for generating a transaction authentication code by the controller; and D3) configuring the processor of the portable electronic device to obtain the transaction authentication code from the smart chip through the memory card interface.