The grapheme was prepared by modified Hummers method,and was characterized by nano laser granulometer and X-ray diffractometer(XRD).The oleic acid and octadecylamine were used to modify the surface of nanoCu particles and the grapheme to improve their dispersion stability in the lubricating oil.The antiwear and friction reducing properties of the graphene/nanoCu composite additive in lubricating oil were evaluated by fourball experiments and cylinderpiston ring variable load friction and wear test.The surface topography of the specimens was observed by metalloscope and scanning electron microscope(SEM),in order to analyze the mechanism of antiwear and friction reducing of the composite additive.The results show that the graphene/nanoCu composite additive has better antiwear and antifriction properties than the single additive of nanoCu or graphene.In the process of friction,graphene and nanoCu are filled on the groove and scratches of the friction surface to make the surface honing more fine.The thin film containing Cu and C elements is formed in the friction surface by the graphene/nanoCu composite additive in the process of friction,which plays the role of selfrepairing.