In this study, a three-dimensional, single-phase model has been established to investigate the performance of proton exchange membrane fuel cell (PEMFC) with serpentine flow fields. The model was operated in the temperature range of 333–353 K, the pressure range of 1–3 atm, gas diffusion layer (GDL) range of 0.3–0.6, both anode and cathode relative humidity range (RH) of 10–100%. The current density and power density of PEM fuel cell was measured according to these varying operation parameters. The V-I characteristic of PEMFC was obtained for these different values of input parameters. The numerical simulation was realized with a PEM fuel cell model based on the FLUENT computational fluid dynamics (CFD) software. The performance of a PEM fuel cell increases with the increase of operating pressure because of partial pressure and diffusivity of reactant gases resulting in decreasing the mass transport resistance. It is also found that temperature has an important effect on the performance of PEMFC by the results of study. Even though after exceeding a definite temperature cell performance decreases. The results showed that the maximum power density was reached with 0.6 GDL porosity, RHa = 100% and RHc = 10% and the value of pressure of 3 atm. Also simulation results were compared with the experimental data reported in literature and showed good agreement between the model and experimental results.