Abstract: The problem of traffic assignment for transit network is discussed. The traffic assignment model for transit network and the time-cost-function of transit flow on the path are established respectively with regard to the characteristics of an interaction and constraint between motor vehicle and transit in the mixed movement. The multipath assignment for transit network comes into use on computer with the iteration method to simulate and predict transit flow. The precision of the model presented can be fairly satisfactory by adjusting certain coefficients and making a number of iterations.