Service processing method and system are provided. The method includes: if it is detected that a first subscriber identity card in a multi-card mobile terminal is performing call service, controlling other subscriber identity card in the multi-card mobile terminal to register with a service network based on a data channel set up by the first subscriber identity card; and during the call service of the first subscriber identity card, if a call service request is received from other subscriber identity card in the multi-card mobile terminal, providing call service to the other subscriber identity card which transmits the call service request based on a data transmission channel set up by the first subscriber identity card. By the method, multi-pass is realized for a multi-card single-pass mobile terminal based on hardware.