Urban traffic congestion has become more and more serious, and the problem of congestion in mountainous cities has become more prominent due to the special geographical form. The implementation of the restriction policy is one of the means to relieve traffic congestion in mountain cities. By constructing a stochastic equilibrium traffic allocation model to describe the traffic operation conditions in mountain city under the restriction policy, the improved Dial algorithm is used to solve the model. Taking the urban area of Chongqing City,China as an example, which has the characteristics of a multicenter city groups, measures are taken to limit the number of vehicles on the working day for the connection channel between the groups to analyze the changes in road traffic and service levels in mountain cities. The study found that the road traffic volume in the central area of the group after the restriction was significantly reduced, and the service level of the road was significantly improved, but traffic congestion also spread to the surrounding areas. Finally, related measures and suggestions for alleviating the proliferation of congestion are put forward.