Copper matrix composites were prepared through spark plasma sintering (SPS) process,mixing fixed amount of reduced graphene oxide (rGO) with the different amounts of Cr.In the sintered bulk composites,the layered rGO network and uniform Cr particles distributed in the Cu matrix.Both of mechanical blending and freeze-drying stages of the wet-mixing process obtained the Cu/Cr/rGO mixture powders,and then SPS solid-phase sintering realized the faster densification of these mixture powders.The hardness and compressive yield strength of the Cu-Cr-rGO composites depicted the higher values than those of pure Cu and single rGO-added composite,and they were gradually increased with increasing Cr.The rGO/Cr hybrid second-phases are believed to be beneficial to strengthening Cu matrix.The relevant formation and strengthening mechanisms involved in Cu-Cr-rGO composites were discussed.