The invention relates to the distinguishing method of random switch-on of time synchronization code divided multi-address system. The time synchronization code divided multi-address system can not distinguish the random switch-on. To solve the said problem, in the invention when the network distributes the channel source which switches randomly, distinguishing the random switch by synchronization code and the random switch of different business can use the different synchronization code. When the network node B detects the synchronization code, and sends the affirming information via the fast physical switch channel, and records the number of fast physical switching channel, the number of frame in the system and the synchronization code. When the terminal switches via the random channel, the node B finds the relative synchronization record, the switching type can be known by the information of synchronization code, and it is convenient to process. The invention can avoid the upgrading of software / hardware, save the system source, and reach a better compatibility backward.