The invention provides a formula of a super hard anti-corrosion coating material for magnesium alloy and a preparation method of the super hard anti-corrosion coating material for the magnesium alloy. The super hard anti-corrosion coating material for the magnesium alloy is prepared from the following raw materials by mixing in parts: 10-15 parts of a pH regulator, 100-200 parts of nano silica sol, 300-400 parts of butyl acetate, 50-80 parts of aluminum dihydrogen phosphate, 100-150 parts of deionized water, 100-120 parts of phenyltrimethoxysilane, 100-200 parts of methyltrimethoxysilane, 75-100 parts of polyester modified organic silicon resin, 75-100 parts of inorganic lampblack pigment, 30-80 parts of anhydrous calcium carbonate, and 30-60 parts of highly methylated amino resin. When the coating material provided by the invention is used, the coating material is sprayed on the surface of the magnesium alloy in a way of spray-coating, and the sprayed coating material is cured by heating; after the coating material provided by the invention is sprayed on the surface of the magnesium alloy, good technical effects of high hardness (9H or above), wear resistance, corrosion proofness and salt-fog resistance (200 hours or above) are achieved.