Abstract: A steady-state, three-dimensional, non-isothermal gas-liquid two-phase mathematical model of the proton exchange membrane fuel cell (PEMFC) was developed to study transport phenomena in the whole fuel cell. This comprehensive model accounted for almost all important transport phenomena in the fuel cell such as fluid flows, heat transfer, mass transfer, electrochemical kinetics and charge transfer, as well as the effect of phase change on mass transfer and temperature field. A special feature of this model was that it allowed detailed modeling and prediction of electrochemical kinetics. The transport of electrons in the backing layer and catalyst layer was accounted for, as well as the transport of protons in the membrane and catalyst layer. Spatial distributions of temperature, species concentrations and current were illustrated and discussed in detail.Lastly,a comparison of predicted performance and experimental data in literature was made to validate the mathematical model.