Abstract: Graphene has a unique two-dimensional structure and properties, which has become one of the ideal reinforcement phase candidates in the preparation of metal matrix composites. Copper has been widely used in electronic products because of its good thermal conductivity, electrical conductivity and chemical stability. But its shortcomings, such as low mechanical strength and low hardness have become a bottleneck problem that need to be solved urgently. At present, the combination of graphene and copper can improve the comprehensive properties of copper matrix materials to a certain extent. However, because graphene is easy to agglomerate and the wettability between graphene and copper is poor, it is difficult to form a good interface between graphene and copper, which leads to the deterioration of the properties of the composites. Therefore, in order to solve the above problem, by chemical reduction method, graphene was modified by reinforcing copper particles on graphene. Finally, the graphene-supported copper composite powder (Cu-rGO) was successfully prepared. Then it was selected the reinforcement phase and mixed with nano-copper powder, and the graphene-supported copper reinforced Cu matrix bulk composite materials (Cu-rGO/Cu) was prepared by the spark plasma sintering (SPS). The effect of the graphene-supported copper composite powder content on the microstructure and properties of copper matrix was studied. The results show that the reduced graphene oxide in the obtained graphene-supported copper composite powder is relatively thin and uniformly distributed with the mass of GO about 50 mg and CuSO₄·5H₂O about 200 mg. Meanwhile, combined with the TEM structure analysis, it is observed that the contact interface between the copper matrix and the reinforcing phase is close, and the introduction of the reinforcing phase can effectively refine the crystal grains of the bulk composite material. In addition, with the increase of the content of reinforced phase, the hardness first increases and then decreases. Especially, when the content is 2wt%, the hardness increases by 17.6%. However, its conductivity and density show a downward trend, which is due to that the oxygen-containing functional groups in the graphene oxide are not completely reduced during the reduction process, and it may be due to the occurrence of defects and agglomeration of the graphene.