Highlights•Polydopamine was used to modify graphene which is facile and environmental.•Spherical Ni NPs can improve the load-bearing capacity of base oil.•The composite can improve the anti-wear and anti-friction performance of base oil.•We report a facile method to prepare metal-nanomaterial composites.In the field of tribology, graphene has become a potential candidate material for lubricating oil and lubricant additives at multiple scales due to their high thermal conductivity and impermeability. In order to further improve the anti-wear and anti-friction properties of graphene, Ni/polydopamine-functionalized graphene composites (Ni/pDA/GR) were successfully prepared by a wet chemical reduction method. In this paper, The GR, pDA/GR, Ni/GR and Ni/pDA/GR were added into the base oil as lubricant additives respectively to explore their lubrication properties. The results showed that the friction coefficient of Ni/pDA/GR group is the lowest, which is about 15 % lower than base oil. Ni/pDA/GR also exhibited good wear resistance in wear tests. At the same time, the optimal concentration of the composite is 0.1 wt% in base oil, and the optimal lubrication load is 5 N.