A method for processing a call in an asynchronous mobile communication system including an asynchronous mobile station, an asynchronous radio network, wherein a synchronous core network is interlocked, includes the steps of: setting up the call in case a calling call message is generated in the mobile station; establishing a channel between the asynchronous mobile station and the asynchronous radio network; handling basic information for assigning a radio resource; performing a cipher establishment; establishing the radio resource; performing a configuration for a service; and transmitting a phone call stand-by message to a user.