The invention discloses a composite material for a gear disk and a preparation method of the composite material for the gear disk. The composite material is prepared from, by weight, 95-98 parts of aluminum, 0.1-0.14 part of bismuth, 0.03-0.05 part of niobium, 0.21-0.23 part of molybdenum, 0.2-0.23 part of carbon, 1.8-2.5 parts of iron, 0.25-0.34 part of silicon, 0.06-0.1 part of cetyl trimethyl ammonium bromide, 3-5 parts of graphene oxide, 5-8 parts of zirconium hydride, 0.8-1 part of hexachloroethane, 0.2-0.3 part of silica sand, 0.25-0.3 part of carboxymethyl cellulose, 0.3-0.35 part of calcium fluoride, 1.2-2 parts of titanium carbide, smaller than or equal to 0.01 part of impurities and a proper amount of deionized water. The composite material has good strength and high elongation percentage, the crack resistance is good, the fatigue resistance is high, the composite material is long in service life when used for the automobile gear disk, the maintaining frequency is reduced, and cost is reduced.