The invention discloses a rubber alloy asphalt modifier with high storage stability. The rubber alloy asphalt modifier is prepared from the following components in parts by weight: 60-70 parts of rubber powder, 5-7 parts of waste plastic, 0.05-0.1 part of glucuronic acid, 15-20 parts of polydimethylsiloxane, 8-10 parts of polyether epoxy resin and 0.00005-0.01 part of graphene powder. Preparationcomprises the steps: (1) waste rubber is crushed into small-particle flocculent rubber powder; (2) the flocculent rubber powder obtained in the step (1) is activated and desulfurized to be regeneratedthrough microwave radiation, and activated rubber powder is obtained; (3) the components are fully mixed, dried, extruded and granulated, and the granular asphalt modifier is obtained; and (4) matrixasphalt is heated, after the modifier is added, the temperature is increased, high-speed shearing and drying are conducted, and then modified asphalt is obtained. According to the prepared modifier,the high-and-low temperature performance of the matrix asphalt can be effectively improved, the storage stability is improved, the adhesiveness between the asphalt and aggregate is increased, storageis easy, the blending, transporting and storage costs are effectively saved, and the production cost is greatly lowered.