Proton exchange membrane (PEM) water electrolysis technology holds significant promise in the field of hydrogen production. To conduct an indepth investigation into the performance and optimization potential of this technology, this paper employs the commercial software Comsol Multiphysics to establish a threedimensional, twophase, nonisothermal fully coupled model of a proton exchange membrane electrolysis cell, taking into account the transport of water within the membrane. The research findings demonstrate that the trapezoidal channel design outperforms the rectangular channel configuration, resulting in a 5.5% performance enhancement at a working voltage of 2.4 V. Through an analysis of water/gas distribution, temperature profiles, membrane water content, and membrane conductivity variations with voltage, it is revealed that the trapezoidal channel exhibits superior gas/liquid transport performance compared to the rectangular channel. At 2.4 V voltage, the trapezoidal channel's anode catalytic layer exhibits a 7.92% increase in water saturation relative to the rectangular channel, a 10.36% reduction in oxygen concentration, a 1.22% elevation in membrane water content, and a 1.75% increase in membrane conductivity, despite the temperature differences within the membrane being relatively insignificant.