Abstract: The effect of substrate surface pretreatment by nitrogen implantation on the adhesive strength and antiwear properties of plasma enhanced chemical vapour deposition (PECVD) TiN coatings was studied. The results showed that, the adhesive strength of PECVD TiN coatings on treated substrate increases and the wear life is more longer than that of the coatings on untreated substrate under oil lubrication ,its service life prolongs by about 10 times under dry friction as the substrate treated by nitrogen implantation. The results of X-ray diffraction (XRD) and electron probe microanalyser (EPMA) analysis showed that, after treating with nitrogen implantation, the TiN(200)peak of the coatings and the interface between the coatings and substrate become wider.