Abstract: Graphite flake (average lateral size of 292 μm and average thickness of 13 μm)/copper composites with high volume fractions (72.08%-93.34%) of graphite flake were produced by a vacuum hot pressing method. Results show that the composites are anisotropic due to the alignment of the surface planes of the graphite flakes perpendicular to the pressing direction. With increasing volume fraction of graphite flakes, the density of the composites decreased from 4.07 to 2.63 g cm^-3, with the relative density apparently decreasing when the volume fraction of the flakes is more than 82.6%. In addition, the in-plane electrical conductivity decreased from 14.71% to 2.45% of the international annealed copper standard, the in-plane coefficient of thermal expansion decreased from 6.6 to 2.2×10^-6/K, the in-plane bend strength decreased from 42.48 to 14.63 MPa, and the in-plane compressive strength decreased from 45.75 to 20.46 MPa while the in-plane thermal conductivity showed a maximum of 663.73 W m^-1 K^-1 at a volume fraction of GF 82.6%. The maximum in-plane thermal conductivity is caused by inter-flake pores that are not fully infiltrated by Cu. The in-plane and out-of-plane thermal conductivity agree well with a modified layers-in-parallel model and a modified layers-in-series model, respectively.