A system for broadcasting wireless data service in a mobile communication system includes sending a request call for a wireless data service from a mobile terminal to a mobile switching center, identifying whether the terminal is registered in the mobile switching center, transmitting authentication code information indicating that the terminal is registered in the base transceiver station, and releasing the corresponding call in the terminal receiving the authentication code information and receiving the wireless service data. The authentication code information may include a Walsh code and a long code necessary for allowing the terminal to reconstitute the data. Through this case information, the system can broadcast wireless service data throughout an entire region and be assured that only mobile terminals storing compatible code information will be able to access the data.