A communication apparatus and a method for MMI displaying are provided, wherein the communication apparatus equipped with at least one subscriber identification module (SIM) cards, comprising: a detector, arranged to detect an amount of the SIM card(s) inserted on the communication apparatus; and a processor, providing different man-machine interfaces (MMIs) to be displayed on a display apparatus according to the amount of the inserted SIM card(s); and wherein when the amount of the inserted SIM card(s) equals to one, the processor provides a single card MMI for a subscriber; when the amount of the inserted SIM cards larger than one, the processor provides a multi-card MMI for the subscribers and examines whether there is a predetermined SIM card being determined; and the different MMIs is displayed based on the predetermined SIM card.