Based on operating principle and performance of high-speed EMUs emergency brake system, AMESim was utilized to establish car pneumatic emergency brake model, vehicle brake submodel and EMUs emergency brake model respectively. On this basis, the composite simulation had been carried out on the established models according to different load, different wheel diameter and different brake mode. The influence of different vehicle parameters on brake performance had been analyzed, and the influence of wind speed and rail slope on brake distance had been researched. The errors by comparing simulation results with the real car test results were within allowable range, which proved the established models in the paper effective. The method to establish the models of brake system provided an effective approach to verify the EMUs emergency brake’s performance for all kinds of high-speed EMUs based on simulation.