Disclosed is a method for determining a wireless communication system by selecting a wireless communication system without considering a corresponding service area. The method includes the steps of: a) if there are any available wireless communication system having identical system type, selecting a wireless communication system having highest priority in the PRL by searching wireless communication system in the first service area and a plurality of second service areas neighbored to the first service area and comparing priories of wireless communication systems in the first service area and second service areas; and d) if there are not any available wireless communication system having identical system type, selecting a wireless communication system having highest priority in the PRL by searching wireless communication system in a plurality of second service areas neighbored to the first service area.