Abstract: Ni-P-TiO₂ composite coating was prepared on the surface of 45 steel by electroless composite plating technology. The microstructure, phase composition and heat treatment properties of the composite coating were studied. The results show that the composite coating is composed of fine cellular substance.Ni, P and TiO₂ particles are evenly distributed in the coating. The structure of the bottom layer of the coating is compact, and there are no holes and other defects. The distribution of cellular substance on the surface layer is discontinuous. The microhardness of the composite coating is higher than that of Ni-P coating. The hardness of the composite coating is further improved after heat treatment. The composite coating has better oxidation resistance below 600 ℃.