Abstract: A transient, three-dimensional, non-isothermal and two-phase mathematical model based on computation fluid dynamics was developed to describe the dynamic process of PEMFC.The developed model was used to simulate a serpentine flow field PEMFC, and the dynamic characteristic parameters such as membrane surface temperature at cathode side and current density during the start-up process of fuel cell were computed.The dynamic response of fuel cell characteristics after step change of cathode inlet velocity, humidity and cell voltage was analyzed.It was found that the start-up and step response time of PEM fuel cell was in the order of seconds, which was similar to the simulation results of most presently used models.