Abstract: To meet the high-efficiency hydrogen production requirements of porous titanium diffusion layers for proton exchange membrane (PEM) water electrolysis, the Ti powders with different powder size were used as the raw materials to prepare the porous titanium plates through powder rolling technology. Subsequently, the gradient porous titanium diffusion layers were obtained with wet spraying and sintering method. The effects of sintering temperature on the pore structure and corrosion resistance were then studied by scanning electron microscope, pore size analyzers, and electrochemical workstation. The results show that, compared to the base materials, the pore structure of the gradient porous titanium diffusion layers is further optimized, and the maximum and average pore size decrease, and the self-corrosion potential is shifted to the positive direction by 218.4, 2.3, and 12.2 mV, respectively, and the self-corrosion current density is reduced from 204.50 μA cm^‒2 to 2.99, 46.29, and 131.70 μA·cm^‒2, respectively, thereby enhancing the corrosion resistance. With the increase of sintering temperature, the average pore size of the gradient porous titanium diffusion layers increases, the maximum pore size decreases, the self-corrosion potential and self-corrosion current density show a trend of decrease and increase, respectively. The Ti91 gradient porous titanium diffusion layers sintered at 900 ℃ have the excellent corrosion resistance, and the self-corrosion potential and self-corrosion current density are ‒65.1 mV and 2.99 μA·cm^‒2, respectively. It is mainly due to the presence of a stable passivation film, which avoids the direct contact between specimen and corrosive medium, slows down the intrusion of the corrosive medium, and thus reduces the corrosion rate.