An event notification method in a wireless communications system can reduce the amount of transmission data in a wireless section and improve transmission efficiency by reducing the number of notifications with respect to an event which is frequently generated as a user sends a server an event notification request message including period information through a SIP-based client in order to request the notification with the specific event, and the server sends an event notification message to the client according to a period included in the period information or when a permitted time range is satisfied in order to notify the event when the corresponding event is generated.