Abstract: The Ni base alloy chromium carbide composite coating was prepared on the surface of 45 # steel using vacuum fusion sintering method. The microstructure and phase construction of composite coating were analyzed by means of SEM and x ray diffraction,and the antiwear property was investigated. The results showed that the composite coating is firmly adhered to substrate,and contains the hard phase with higher ratio. Adding chromium carbide can obviously increase the antiwear property of coating. In the given conditions,the antiwear property of Ni base alloy chromium carbide composite coating is 5 fold and 20 fold higher than those of 45 # steel under dry or 20 # machinery oils lubrication respectively.