Proton exchange membrane fuel cells have been receiving more and more attention these recent years. It is expected to improve the output power of the fuel cell, so it is important to understand what are the relevant factors affecting the output power. Simulation can provide valuable insight and guidance for design, performance optimization, and cost reduction of fuel cells. Some factors which affect the generated output of proton exchange membrane fuel cell are study in this paper, and simulation results are shown and analyzed. It helps to understand the mechanism of the fuel cell and lay a good foundation for improving the output power.