User card balance data processing method and system

The embodiment of the invention provides a user card balance data processing method and system. The method comprises the steps that a mobile terminal starts a card reader; the mobile terminal reads data card identification information of a user data card read by the card reader; the mobile terminal receives balance pre-decrement information input by a user; the mobile terminal sends the balance decreasing request information to an application interface server, wherein the balance decreasing request information comprises the data card identification information and the balance pre-decrement information; the application interface server sends the balance decreasing request information to an application server so as to enable the application server to correct the user card balance data corresponding to a data card identifier and enable the user card balance to be decreased by the amount corresponding to the balance pre-decrement and processing result information is fed back to the application interface server. The user card balance data processing method and system can process the user card balance data conveniently and quickly and reduce the error rate.