The invention discloses a method and a password card used for processing communication service data. The method includes: carrying out identity authentication and key negotiation on on a terminal, which accesses a service system, to establish a communication relationship of the service system and the terminal; using a session key to encrypt site output data, which are sent by the service system tothe terminal, to generate encrypted site output data, encapsulating the encrypted site output data, then generating first service data, and sending the same to the terminal; and parsing encapsulatedsecond service data, which are sent by the terminal, to obtain encrypted site input data, using the session key to decrypt the encrypted site input data, obtaining unencrypted site input data, and sending the same to the service system. According to the method, frequent operation IO in a communication service data processing process can be reduced, protocol processing efficiency is improved, the session key is maintained inside the password card, and a case where the session key appears in system RAM can be effectively avoided.