In this work, we present a simple and feasible method with broad applicability for the in-situ reduction and assembly of graphene lubricant films on various substrates. We adopt graphene oxide hydrosol as the precursor solution and creatively introduce an adherent coating of polydopamine that can be firmly bonded onto a wide range of substrates and acts as an active transition layer and in-situ reducing agent, aiming at obtaining the reduced graphene oxide (rGO) films thereon without addition of exogenous reducing agent. Experimental results prove that rGO nanosheets have been successfully assembled onto the substrates and the in-situ synthesized rGO film presents excellent morphology, outstanding friction reduction and wear resistance properties.