In this paper, the diffusion behavior of Cu/Ni/Ti atoms at different temperatures was studied by means of diffusion heat treatment. The influence of diffusion process on the structure and corrosion of the coating was also discussed. The results show that the corrosion resistance of the coating surface can be effectively improved with the stable diffusion layer formed by the mutual diffusion of Cu/Ni/Ti atoms. As the thermal diffusion temperature up to 700 ℃, the compact structure of membrane layer, the NixTiy intermetallic compounds and a small amount of CuxTiy intermetallic compounds formed in the diffusion layer, the corrosion resistance of coating on the surface of the best. Temperature to 800 ℃, Kirkendall space grew up together each other, which is formed by the formation of cracks or holes and make coating porous, so as to lower the corrosion resistance, due to Kirkendall effect is triggered by atoms at the interface between Cu/Ni/Ti structure.