A preparation method for a metal-based three-dimensional graphene composite material comprises the steps that 1, metal powder is put in a growing vessel; 2, the growing vessel is put into a chemical vapor deposition furnace to be sintered under the protective atmosphere at the sintering temperature of 500-1050 DEG C, and block-shaped foam metal of a three-dimensional net structure is prepared; and3, growing gas is injected, a graphene film directly grows on the surface of the block-shaped foam metal at the temperature of 500-1050 DEG C, and the metal-based three-dimensional graphene compositematerial is formed. The prepared foam metal is small in metal pore size, large in metal pore quantity, low in cost and suitable for industrial production; and three-dimensional graphene directly grows on the surface of the foam metal of the three-dimensional net structure, the graphene film of the prepared metal-based three-dimensional graphene composite material is uniform and continuous, the mass percent of the graphene in the composite material is high, and the electrical conductivity of the composite material is advantageously improved.