A cellular mobile communication network in a code division multiple access system includes plural base stations covering cells, respectively, a host base station communicable with the plural base stations and plural mobile stations moved in the cells; when a mobile station becomes uncontrollable, the base station communicating the failure mobile station requests the host base station to register the identity code of the failure mobile station in a list of failure stations, and changes the control channel from an original radio frequency to a new radio frequency without informing the failure mobile station of the new radio frequency so as to disconnect the failure mobile station from the cellular mobile communication network; when another mobile station transmits a request for communication to a base station, the base station inquires the host base station whether the request is acceptable or not, and the host base station checks the list to see whether the identity code of the mobile station has been already registered; thus, the failure mobile station never communicates with the base stations, and does not serve as a serious interference power source.