A combo communication terminal has a first communication terminal and a second communication terminal. A switch unit of the second communication terminal has a first end, a second end, a third end and a control end. The control end selectively couples the first end to the second end or to the third end according to a control signal. When a communication link between the first communication terminal and the second communication terminal has been established, a second processing unit of the second communication terminal generates and transmits a first control signal to the control end, such that a first processing unit of the first communication terminal is coupled to a first subscriber identity unit of the second communication terminal via the first port, so that the first communication terminal uses the first subscriber identity unit to perform tasks of communication.