The condition of the reaction site at different pressure determines a vital part of transport phenomena. At high pressure, the amount of water saturation is higher, the uniformity of oxygen at the reaction site is low, and the concentration of unconsumed oxygen at the reaction site is more. Although, after medium pressure, the amount of current density decreases, the amount of oxygen at the reaction site increases, which is the sign of lower performance of MEA. Lower oxygen gradient and oxygen uniformity at reaction site, higher saturated water, and unconsumed oxygen caused higher resistance and worse water management. The interaction of anode stoichiometry and cathode stoichiometry is decisive in determining water saturation. Figure shows the effect of stoichiometries interaction on water saturation. Simultaneous high stoichiometries bring worse water management, and low stoichiometries lead to lower water saturation. optimum features. Therefore, the resistance in GDL was low. In some cases, GDL resistance can be several times larger than MEA resistance.