Abstract: Rate earth elements can improve the structure of Ni-base alloy spray-welding coating and increase its wear-resistance and load bearing capacity.In order to clarify the mechanism of rare earth elements on the coating,investigated the effect of rare earth elements on oxide films formed on the friction surface of this alloying coating was investigated using XPS,AES and SIMS.The results showed that rare earth elements can obviously increase the thickness of oxide film formed on the friction surface of coating and can be enriched between oxide film and substrate,that play an important role for strengthenning the bonding strength of coating with substrate and for increasing the wear-resistance and load bearing capacity of spray-welding coating.