The invention discloses an antirust composite material and a preparation method thereof. Raw materials for preparing the antirust composite material comprise 40-60 parts of zinc magnesium aluminum alloy, 100-140 parts of composite fiber, 2-6 parts of a plasticizer, and 4-10 parts of an antioxidant; the zinc magnesium aluminum alloy comprises 1.0%-2.5% of zinc, 2.0%-4.5% of magnesium, and the balance aluminum; and the composite fiber is combination of one or two of carbon fiber and alumina fiber. According to the antirust composite material, existing deficiencies are overcome, and the problemsthat an existing composite material is simple in function, complex in manufacturing process, large in material consumption and time consumption, high in labor cost and high in production cost are solved specifically; the antirust composite material has the special effect of rust prevention, and the problems that the antirust and anti-corrosion ability of metal alloy materials is poor and the strength and the anti-impact ability of common composite materials are poor are solved; and meanwhile, the performance of the antirust composite material is improved, toughness is sufficient, abrasion resistance and corrosion resistance are achieved, the anti-impact ability is high, the preparation process of the antirust composite material is simple and reasonable, and the antirust composite materialand the preparation method thereof can be widely used.