Abstract: Proton exchange membrane fuel cells（PEMFC）are efficient and environmentally friendly energy conversion devices with broad application prospects in multiple fields. To achieve stable and reliable operation of high-power vehicle-mounted PEMFC systems,this study focuses on modeling a 70 kW high-power fuel cell system,a model of proton exchange membrane fuel cells（PEMFC）system was proposed based on the Simulink platform. With the proposed system model,the effects of temperature,membrane water content and pressure on the output performance of PEMFC were studied under the steady state,and the transmembrane transport of water and gas was analyzed. Simulation results indicate that the stack output voltage remains stable when the current density is within the range of 0.4-1.0 A/cm~2. The dynamic condition of NEDC was also applied and analyzed. The results show that the proposed model can be used in studying high-power PEMFC for automotives.