The invention discloses a method for implementing a mobile phone number changing notification service. The method adopted can smoothly guide a calling party to remember to dial a new number of a user after number changing. The method comprises the following steps: A, dividing a period of validity of a number changing service into a plurality of stages, and respectively setting the duration of each stage and a corresponding processing mode of each stage aiming at the calling party who dials the old number before the number changing, wherein in the processing modes, when the stages are more close to the end, the calling party is less considered; and B, when the calling party dials the old number before the number changing, adopting the processing mode corresponding to the positioned stage. In the step A, the period of validity of the number changing service can be divided into three stages, and the processing modes of the stages are respectively that: in the first stage, the calling party is notified to dial the new number of the user after the number changing, and the call for the time is switched to the new number; in the second stage, the calling party is notified to dial the newnumber of the user after the number changing, but the call is not switched to the new number; and in the third stage, the calling party is notified that the dialed number is a vacant number.