In order to improve the thermal conductivity of thermal interface materials, reduced graphene oxide/copper composite materials were prepared by electrophoretic deposition, and the effects of reduced graphene oxide/copper, multilayer graphene and nano-silver on the thermal conductivity of epoxy resin were compared and analyzed. The microscopic morphology of the reduced graphene oxide/copper composite material was characterized by scanning electron microscopy. Thermal constant analyzer, digital viscometer and contact thermal resistance tester were used to control and test the thermal conductivity, viscosity and interface thermal resistance of epoxy resin-based composite thermal interface materials. The results show that the experiment successfully prepared reduced graphene oxide/copper, and the metal copper particles were evenly distributed between graphene sheets; in addition, the thermal conductivity of reduced graphene oxide/copper, multilayer graphene, and nano-silver to epoxy resin both have improved. When the mass fraction of the reduced graphene oxide/copper composite material is 30%, the thermal conductivity of the epoxy resin-based composite thermal interface material is increased by 4.5 times. Under a pressure of 0.9 MPa, the interface contact thermal resistance is 37.06 mm2
, which is 35.9% lower than when no interface material is added (the interface contact thermal resistance is 57.84 mm2
when no thermal interface material is added.). High thermal conductivity materials can increase the thermal conductivity of epoxy resin-based thermal interface materials and significantly improve the heat transfer performance of the contact surface.