The invention discloses a method for simulating the coupling between a vehicle and a traction network and a power system, which comprises: firstly, combining the computation of the traction network and the computation of the tidal current of the traction network; secondly, every time a stable result is obtained by the iterative computations of the traction network and the power system, performingthe electric vehicle simulation under the condition of a stable result; and finally, performing the correction computation of the traction network and the power system by using the result of the simulation of the electric vehicle till the electric vehicle, the traction network and the power system all reach a stable state. Compared with the conventional traction network computation method, the method for simulating the coupling between the vehicle and traction network and the power system of the invention has the advantages that: the influences of the vehicle and the power system on the traction network are taken into full consideration; on the premise of keeping good computation efficiency, the accuracy of the result of the computation of the traction network is improved greatly and mademore in accordance with actual conditions; and the needs of railway/power related departments for traction power supply quality evaluation and electric quality estimation.