Abstract: The composites of reduced graphene oxide/lanthanum fluoride (rGO/LaF₃) have been successfully synthesized through a simple strategy combining liquid phase chemical reaction and hydrothermal process. The tribological properties of series samples as water-based lubricant additives were evaluated by the friction and wear tests, which were carried out on an Optimol SRV-I oscillating reciprocating friction and wear tester. The profile of the wear scar and the volume of wear track were determined by a three-dimensional (3D) surface profiler. The results indicated that the introduction of rGO/LaF₃ (weight fraction 0.1%) into the pure water could achieve the goal of reducing friction and wear, which was better than the single rGO.