In the background of energy saving and emission reduction and carbon neutrality in various countries, hydrogen energy as a widely sourced and pollution-free secondary energy has received widespread attention. Proton-exchange membrane fuel cell (PEMFC) can realize the conversion of hydrogen energy to electric energy. The conversion process has the characteristics of high efficiency and zero pollution. The application of PEMFC in transportation is the best choice to achieve deep decarbonization in transportation. To study the output characteristics of PEMFC, by deeply understanding its working principle and electrochemical reaction process, an open circuit voltage model and three voltage loss models were established. Considering the double-layer charge layer effect of PEMFC, a monomer simulation model was established, and the model was simulated in MATLAB/Simulink. The effects of operating temperature, working pressure, and water content of Proton-exchange membrane (PEM) on the output performance of fuel cells were studied. The results indicate that increasing the operating temperature, operating pressure, and appropriately increasing the water content of PEM can help to increase the output voltage of fuel cells and improve their performance. The research conclusion will provide reference for the design and practical application of PEMFC.