In this paper, a three-dimensional multiphase model of the polymer exchange membrane (PEM) fuel cell is simulated to study the effect of assembly pressure on the contact resistance between the gas diffusion layer (GDL) and bipolar plate (BP) interface. The results reveal that the increase of assembly pressure is associated with a decrease in the contact resistance between the GDL and BP interface, which results in reaching an ideal fuel cell performance. The performance improves until the assembly pressure of 4.5 MPa and it slightly drops with a clamping pressure of 5.5 MPa in the ohmic loss region of the polarization curve. Additionally, the variation of the electrical field in a cross-section of the channel length shows that the intrusion of GDL into the flow channel increases with increasing assembly pressure; consequently, the maximum electrical current will increase. The cell temperature rises at higher assembly pressure when considering the thermal contact resistance. This increase is higher on the cathode side because of the existence of the reaction heat source. Additionally, it is found that the distribution of electrical potential and oxygen concentration is more uniform at higher clamping pressure. This results in the development of the PEM fuel cell life cycle. (C) 2019 Elsevier Ltd. All rights reserved.