Corrosion in sulfate solutions is one of the normal ways of concrete failure, and thus researching anti-corrosion methods of concrete against sulfate solution is of great significance to concrete projects. The corrosion process of concrete in sulfate solution is gradual, and it involves the interface adsorption on the surface of the solid-liquid, diffusion process of the sulfate solution and the processes of chemical reaction and physical crystallization of sulfate inside specimens. Our research shows the second Fick diffusion law can be used to describe the diffusion process of concrete in sulfate. When concrete specimens are immersed in sulfate solution, there are physical adsorption and chemical adsorption on the solid-liquid interface, and chemical reactions on the surface.