Abstract: A non-isothermal three-dimensional(3 D) two-phase flow transport model is developed for a proton exchange membrane fuel cell(PEM FC) with straight flow channels.Based on characteristics of water transport between membrane and gas phase,a non-equilibrium model is developed for liquid water transport in membrane,considering electroosmosis,concentration diffusion and electrochemical reaction.A finite volume method is used to discretize governing equations and solution code is developed.The model is used to simulate multi-physical field coupled transport in a PEMFC.Investigations are performed for water vapor concentration,liquid water saturation,membrane water content distribution and liquid water transport velocity.Temperature field inside a cell and predicted polarization are obtained.