Disclosed herein is a method for manufacturing a sound insulation material, a sound insulation material manufactured using this manufacturing method, and a carpet for a vehicle using the sound insulation material, and the sound insulation material is manufactured using a composite resin composition including 30 parts by weight to 70 parts by weight of aluminum oxide, 10 parts by weight to 20 parts by weight of nanoclay, 0.2 parts by weight to 0.8 parts by weight of an antioxidant, and 0.1 parts by weight to 0.5 parts by weight of a lubricant, with respect to 100 parts by weight of a base resin including PE, and the carpet for a vehicle is manufactured by coating the sound insulation material on a carpet fabric material and drying the result.