The work aims to prepare electroless Ni-P coating on titanium alloy surface and study effect of rare earth on properties. SEM and EDS were used to test thickness and composition of chemical plating; XPS was adopted to analyze valence state of rare earth element in plating coating; XRD was taken to analyze composition of plating coating through different heat treatments; microhardness tester was used to test hardness of plating coating through heat treatment; and electrochemical test was conducted to characterize corrosion resistance of titanium alloy and plating coating through heat treatment. Rare earth-modified thick coating was composed of a 70 μm NiP layer and a 30 μm Ni-P-Ce layer. The coating was formed by three elements including Ni, P and Ce with respective mass fraction of 89.94%, 10.03% and 0.03%. The element Ce was composed of three valence states of +4, +3 and 0. With the increase of heat treatment temperature, the coating gradually changed from amorphous to crystalline. The transformation occurred at 200~300 ℃ and the composition also changed. The hardness of coating increased and reached 1000HV after heat treatment at 400 ℃. The coating could effectively improve the corrosion resistance of titanium alloy substrate, but the corrosion resistance dropped dramatically as the heat treatment temperature increased. The optimum heat treatment temperature was 200 ℃ (the corrosion current density and polarization resistance were 0.2445 μA/cm2 and 155.464 kΩ respectively). The coating modified by rare earth was 100 μm thick plating coating. Rare earth cerium, nickel andphosphorus are co-deposited on the titanium alloy due to reaction. The heat treatment temperature has obvious influence on crystallization mode, composition and hardness, especially corrosion resistance.