The invention relates to the filed of mobile communication business, and aims at providing a method for judging and differentiating user busy state through testing calling, which comprises the following steps: a business system sends IAM initial address messages to a called exchange board of a called party and waits; if the called party is free, the called exchange board recalls business platformACM full address messages after receiving terminal response; if the called party is in communication, the called exchange board can recall the business platform ACM full address messages without initiating paging; a business system is in communication when receiving the ACM messages before the time-out threshold reaches; and the called party rejects the calling when not receiving the ACM messagesafter the time-out threshold reaches. The invention can realize the judgment and the differentiation of the busy state of the movable user by using a signal monitoring and analyzing technology through the IAM initial address messages sent by the business system and the ACM full address messages responded by the called party without changing the prior calling business process and the prior networkequipment.