Liquid water saturation in the cathode porous electrode plays an important role in PEM fuel cell performance and mass transport. In this paper, a steady-state, two-dimensional, two-phase flow mathematical model for PEM fuel cell is presented. The model couples continuity equation, momentum equation and species conservation equations. Net water transport flux in the membrane is considered as a boundary condition. The effect of fuel cell temperature and pressure on its performance is investigated by experiment and simulation. The modeling results compared well with the experimental data. The results of simulation showed that the liquid water saturation on the interface between the cathode CTL and GDL increases significantly with the increase of fuel cell pressure and the cathode humidification temperature, the effect due to the increase in the anode humidification temperature is negligible, and that the saturation decreases with the increase of fuel cell operation temperature.