A multi-interface card includes smart card interface, memory card interface, card controller and memory module. The smart card interface interfaces with a smart card host using a smart card protocol. The memory card interface interfaces with a memory card host using a memory card protocol. The card controller controls the smart card host and memory card host so that the smart card host and the memory card host simultaneously interface with the smart card and the memory card interfaces, respectively. The memory module stores data transferred from the smart card host and memory card host. The multi-interface card simultaneously supports the smart card interface and the memory card interface. Thus, the one multi-interface card can support a subscriber authentication function and a data storage function.