A global sensitivity technic enhanced by variance method is applied to a model that simulate the power output of a proton exchange membrane fuel cell (PEMFC). The objectives are to demonstrate how the global sensitivity method is applied to a PEMFCs theoretical model and to visualize the sensitivity indices of partial pressure of reactant gases, temperature, current density, membrane cross section and thickness, gas diffusion layer porosity and thickness on the power performance of the PEMFC. Results show that the current density, temperature, membrane thickness, gas diffusion layer thickness and porosity, are the sensitive parameters with the dominant influence from the current density and membrane thickness. In addition, it is found that the pressure of hydrogen, pressure of oxygen and membrane cross section are the relatively lesser sensitive parameters. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.