The mathematical model of PEMEC is established in Matlab/Simulink. Based on the charge and mass balance at the electrode surface and Butler-Volmer dynamic, a model is developed to explain the current and potential characteristics of electrolysis. The effects of different PTL parameters on the performance of PEMEC are studied by the model. Display omitted •The voltage of PEMEC decreases with the increase of temperature within a certain range.•The thickness of PTL is gradually reduced from 2 mm to 0.5 mm, and the performance of PEMEC would be improved with the decrease of PTL thickness.•The decrease in porosity will increase the resistance of PTL. The effect of pore size on the performance of PEMEC is smaller than that of porosity. Porous transport layer (PTL) is one of the most important components in proton exchange membrane electrolyzer (PEMEC). In this study, a mathematical model of PEMEC is established in MATLAB/Simulink. The effects of different PTL parameters on the performance of PEMEC were studied. The results show that the increase in PTL thickness and porosity can increase the ohmic overpotential and reduce the performance of PEMEC. As PTL pore size decrease, the performance of PEMEC improves. The influence of pore size on the performance of PEMEC is smaller than that of porosity.