Abstract: Graphene has been considered as an ideal reinforcement filler for metal matrix composites because of its ultra-high strength and stiffness, and exceptional thermal and electrical properties. Graphene-reinforced copper (Gr/Cu) nanocomposites were fabricated by ball milling followed by pressureless vacuum sintering, and were characterized by SEM, TEM, XRD, Raman spectroscopy and mechanical tests. Results indicate that the graphene platelets are well dispersed in the nanocomposites without apparent damage. The graphene filler dramatically improves the hardness and reduces the coefficient of friction of the Gr/Cu nanocomposites compared to pure Cu.