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