A method for cell selection of an asynchronous mobile station in an asynchronous mobile communication system including an asynchronous mobile station, an asynchronous radio network, in case the asynchronous mobile communication system is interlocked with a core network, includes the steps of: storing information related to the core network transmitted from the asynchronous radio network in a memory or a user subscriber identity module (USIM) of the asynchronous mobile station before power-off of the asynchronous mobile station of the asynchronous mobile station; at power-on of the asynchronous mobile station, determining what type of the core network is interlocked by analyzing the information of the core network; beginning any one of a global system for mobile communication (GSM) cell procedure and an American national standards institute (ANSI) cell procedure; finding a cell suitable for providing a service, based on a type of the core network that was determined; and performing a location registration of the found cell.