The passenger flow assignment of subway networks plays an important role in the operation and management of urban rail transit networks． As the influence of the train capacity constraint on the passenger flow assignment in a schedule-based network is seldom taken into account in relevant literature，this paper constructs a dynamic assignment model of passenger flows under the condition of the stochastic user equilibrium，and designs a solution algorithm by establishing a schedule-expanded network and by designing corresponding k-shortest path search algorithm． Moreover，the congestion and overload delay under the train capacity constraint are also taken into account． Then，the proposed model is verified by a numerical example in Beijing subway networks，and the parameter sensitivity is analyzed． The results show that the proposed model is of a rapid convergence and a higher degree of accuracy with a relative error of 9. 5% ～11. 2%，which can meet the requirements of analyzing and estimating the passenger flow distribution in a large-scalesubway network．