TiN and C:N coatings are made on 20CrMo gears by PVD(Physical Vapour Deposition) technology and DFAD(Direct current Filtered Arc Deposition) technology. Then the authors puts forward the test rig, working under the conditions of 1 800 rpm,12 N.m for 50 h, and the observations by body-microscope show that reducing wear and anti-wearing performance greatly enhanced when C:N film is used, TiN coatings can however, because the hardness of gears is evidently decreased when coating was processing. Direct current Filtered Arc Deposition(DFAD) technology are used on gears to improve the performance of reducing wear and anti-wearing.