Abstract: Urban rail transit network operation robustness was quantitatively studied by stochastic user equilibrium theory.Under the assumption of child network without a station or route and its affect range,passenger flow assignment models separately based on fixed and elastic demand stochastic user equilibrium were used.Nine urban rail transit network operation robustness indices were proposed considering relative fluctuation of passenger flow,time and all the time of passenger flow.The key station and the key route of network,which lost from the network affecting operaion indices mostly,were identified obeying the least indice principle.A numerical example indicates that the research of this paper is feasible and effective,and robustness indice value range of losting station is much greater than that of losting route.