Abstract: Carbon nanotube was used as a reinforcing agent to prepare Ni-matrix composite coating. The tribological behavior of the composite coating in reciprocating sliding against AISI-52100 steel was examined on an Optimol SRV friction and wear tester. The surface morphologies of the coatings before and after the friction and wear test were analyzed with a scanning electron microscope. The friction-reducing and wear-resistant mechanisms of the carbon nanotubes in the Ni-carbon nanotube composite coating are also discussed. As the results, the carbon nanotubes were uniformly embedded in the coating matrix and one end protruded from the surface. Ni-carbon nanotube composite coating has better wear resistance and self-lubricity than the Ni coating.