The present invention provides a method for associating a user with a base station based on backhaul capacity in heterogeneous cellular network. First, an available base station set is obtained through the SINRs, and the downlink data rate between the new user and each base station in the available base station set is calculated according to the SINR between them; Then, the usable link capacity factor of each base station is calculated based on the used link capacity and the backhaul capacity; Finally, the optimal base station is selected for the new user i under a constraint which is constructed by the bandwidth of the new user and the usable link capacity factor. The backhaul capacity of each base station is taken into account in selecting the optimal base station to associate with for the new user, thus the real time of user association and the overall performance of heterogeneous cellular network can be guaranteed.