Proton exchange membrane water electrolysis (PEMWE), also known as polymer electrolyte membrane electrolyte water electrolysis, is a technology that converts electricity into hydrogen （H2） and oxygen （O2）. The bipolar plate (BP), akey component, is directly connected to the porous transport layer (PTL) on both the anode and the cathode sides. Steam is fed into the BP on the anode side, where water vapor is distributed across the PTL and enters the anode catalyst layer. Here, the water undergoes electrolysis, producing O2 and H+. The protons are transferred to the cathode side through the PEM, whileO2 is vented back to the BP’s gas channel. The BP is crucial for efficiently supplying reactant gases and venting the gas products. In this paper, the transport properties of a round BP with a PTL are analysed using 3D computational fluid dynamics (CFD). A mixed flow channel design, combining annular and baffle channels), is evaluated by comparing fluid flow and mass transport. Simulation results show that the mixed channels design with openings demonstrates better performance.