We investigated the synthesis process of Cu-RGO flake in order to control agglutination of interfaces, and the manufacturing process of Cu-based composite materials using the spark plasma sintering. The GO(Graphene oxide)-CuOx was synthesized by hydro-thermal method at 80℃ for 5 hours. The annealing reaction was carried out at 800℃ for 5 hours in argon and hydrazine ambient to obtain synthesized Cu-RGO flakes. The morphology and structure of synthesized Cu-RGO flakes were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. The synthesized Cu-RGO flakes and copper powders were mixed by vibrator. Also, SPS sintering was carried out at 600℃ for 5 min under 100 MPa. Thermal diffusivity were characterized by laser flash method at the temperatures of 50~150℃.