SBS asphalt modifier and preparation method thereof, modified asphalt based on asphalt modifier and preparation method thereof

The invention discloses an SBS asphalt modifier and a preparation method thereof, and modified asphalt based on the asphalt modifier and a preparation method thereof, the SBS asphalt modifier comprises an SBS modifier and assistants, and the assistants comprise cellulose acetate, a diluent, a pore-foaming agent, sulfur, a vulcanizing agent, an activating agent and a curing agent. The modified asphalt comprises matrix asphalt, an SBS modifier accounting for 2-4% of the matrix asphalt and an auxiliary agent accounting for 1-2% of the matrix asphalt; the preparation method comprises the following steps: heating the matrix asphalt to 170-180 DEG C, adding the SBS modifier, shearing, adding the auxiliary agent, and stirring for development. The assistant adopted by the SBS asphalt modifier can form a structure that a vulcanizing agent core material is coated with a porous cellulose acetate high polymer, so that active sulfur of the core material can be slowly released to realize crosslinking of the SBS modifier an