The invention provides a method for relieving network congestion. Firstly theoretical mean waiting time of a user in a certain period, which is as shown in a formula (I), is calculated by telephone traffic and call intensity in the period, wherein, nRho is network telephone traffic, n is the number of time slot used for communication in a GSM cell, Rho is network utilization. A formula (II) represents a network free probability; 1 virgule Mu represents a user mean call time and the telephone traffic is divided by the call intensity to obtain the user mean call time; secondly an artificially added waiting time w1 is obtained on the basis of maximum time limit which the user is capable of tolerating; finally based on a waiting time of the user in a single server queue system, the average service rate Mu' of the single server queue system in the period is adjusted. The invention has the advantages that no additional resource is required to be inputted, network capacity can also be increased; only a processing delay is added when the system responds the request of the user, which is beneficial to system implementation; the problem of the network congestion can be solved to a certain extent, etc.