An intelligent portable communications device and its operation method according to a user's schedule are provided. The operation method is formed of the steps of recording the schedule, continuously determining if it is necessary to alert the user, determining if the user has a scheduled event if alerting the user is necessary, determining if the user can be called during a scheduled event, automatically performing a response corresponding to the recorded schedule for the call if the user cannot be alerted, and alerting the user if the user can be alerted, or if the user does not have the scheduled event. Therefore, even though the user has not manipulated the portable communications device before a scheduled event, the user is not disturbed, a noise interruption can be prevented, and the caller can be led to conform to the user's schedule through the automatic response function.