Hydrogen fuel cells for vehicles are susceptible to changes in the external environment and operating conditions in practical applications, and there are problems such as unstable voltage output, large hysteresis, and fuel safety, which seriously hinder the commercial application and promotion of fuel cells. Establishing a more accurate fuel cell system model can more effectively simulate and optimize. In this paper, a hydrogen fuel cell system model is established by combining mechanism modeling and identification modeling. In order to establish the hydrogen fuel cell system model, the combination of mechanism modeling and identification modeling was used. A semi-empirical model of output voltage and output power is established according to the actual situation of the stack. According to the working principle of the fuel cell system, the mechanism model of the fuel cell air supply system and hydrogen supply system is established,and the simulation analysis is in Matlab/Simulink. The model can effectively reflect the static and dynamic changes of key parameters such as the operating pressure of the stack, the stack temperature, the working pressure difference between the anode and the cathode, and the excess oxygen ratio. The relationship curves of output voltage and output power with load current under different working conditions were drawn. From the graph, the effect of the changes of different parameters on the operation of the fuel cell is obtained.