Abstract: The effects of parameters on the performance of PEMFCs with conventional flow field operating with air were discussed, including diffusion factors, the geometric parameters of flow field, the resistance of electrode, the activity of catalyst and O₂ concentration in the flow channels， with the mathematical model developed in part I. The limiting current density would increase with increasing oxygen effective diffusion coefficient and decreasing electrode thickness. The performance of PEMFCs would be promoted with increasing exchange current density of oxygen reduction reaction, decreasing resistance of electrode and optimizing geometric parameter of flow field. The uniformity of current density distribution could be improved by increasing catalyst loading along the gas flowing direction.