This study presents a novel approach to enhance the performance and stability of proton exchange membrane water electrolysis (PEMWE) by optimizing stress distribution in the electrolyzer assembly. The research demonstrates that the conventional serpentine flow channel (S-FC) leads to uneven stress distribution, causing severe deformation of the anode catalyst layer (ACL) and poor electrical contact, which negatively impacts efficiency and durability. In contrast, a titanium mesh flow channel (TM-FC) with a gradient pore size distribution effectively reduces stress inhomogeneity, leading to improved performance and stability. The TM-FC significantly reduces the initial voltage by 27 mV and decreases the voltage degradation rate by 8 times compared to the S-FC at 2.0 A/cm². Furthermore, the TM-FC was tested in cross-scale electrolyzers up to 100 kW, showing only a 20 mV voltage increase after three orders of magnitude scaleup, which is less than 2% of the overall voltage. The study also shows that the TM-FC maintains a uniform stress distribution, enhancing the contact between the porous transport layer (PTL) and ACL, which improves in-plane electron transport and overall performance. The ACL-TM-FC demonstrated superior durability, with a degradation rate of less than 10 μV/h, compared to the ACL-S-FC, which had a degradation rate of over 60 μV/h. The TM-FC also showed better performance under different operating conditions, including varying cathode back pressures and iridium loadings. The study concludes that the optimized TM-FC significantly enhances the performance and durability of PEMWE, making it a promising solution for large-scale clean energy production. The findings highlight the importance of stress distribution optimization in improving the efficiency and stability of PEMWE systems.This study presents a novel approach to enhance the performance and stability of proton exchange membrane water electrolysis (PEMWE) by optimizing stress distribution in the electrolyzer assembly. The research demonstrates that the conventional serpentine flow channel (S-FC) leads to uneven stress distribution, causing severe deformation of the anode catalyst layer (ACL) and poor electrical contact, which negatively impacts efficiency and durability. In contrast, a titanium mesh flow channel (TM-FC) with a gradient pore size distribution effectively reduces stress inhomogeneity, leading to improved performance and stability. The TM-FC significantly reduces the initial voltage by 27 mV and decreases the voltage degradation rate by 8 times compared to the S-FC at 2.0 A/cm². Furthermore, the TM-FC was tested in cross-scale electrolyzers up to 100 kW, showing only a 20 mV voltage increase after three orders of magnitude scaleup, which is less than 2% of the overall voltage. The study also shows that the TM-FC maintains a uniform stress distribution, enhancing the contact between the porous transport layer (PTL) and ACL, which improves in-plane electron transport and overall performance. The ACL-TM-FC demonstrated superior durability, with a degradation rate of less than 10 μV/h, compared to the ACL-S-FC, which had a degradation rate of over 60 μV/h. The TM-FC also showed better performance under different operating conditions, including varying cathode back pressures and iridium loadings. The study concludes that the optimized TM-FC significantly enhances the performance and durability of PEMWE, making it a promising solution for large-scale clean energy production. The findings highlight the importance of stress distribution optimization in improving the efficiency and stability of PEMWE systems.