High-modulus modifier composition of asphalt mixture

The invention discloses a high-modulus modifier composition of an asphalt mixture. The composition comprises polypropylene, low density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, dicyclopentadiene-phenol epoxy resin, composite fibers, calcium sulfate whisker, hydroxypropyl methyl cellulose, rock asphalt, polyethylene grafted maleic anhydride, oleic acid, calcium stearate, butyl palmitate, Tween80, oxidized polyethylene wax, an antioxidant and a coupling agent. The modifier can be used in the asphalt mixture to improve the modulus, the rut resistance, the water stability and the low temperature crack resistance of the asphalt mixture, can maintain the mixing property of the original asphalt mixture and improves the comprehensive performances of the asphalt mixture.