The present work is employed in two sections. Firstly the effect of different parameters such as pressure, temperature and anode and cathode channel depth on the performance of the proton exchange membrane (PEM) fuel cell was experimentally studied. The experimental result shows a good accuracy compared to other works.Secondly a semi-empirical model of the PEM fuel cell has been developed. This model was used to study the effect of different operating conditions such as temperature, pressure and air stoichiometry on the exergy efficiencies and irreversibilities of the cell. The results show that the predicted polarization curves are in good agreement with the experimental data and a high performance was observed at the channel depth of 1.5 mm for the anode and 1 mm for the cathode. Furthermore the results show that increase in the operating temperature and pressure can enhance the cell performance, exergy efficiencies and reduce irreversibilities of the cell.