SBS modified asphalt and preparation method thereof

The invention provides SBS (Styrene Butadiene Styrene) modified asphalt which comprises the following components in parts by weight: 100 parts of matrix asphalt, 3-10 parts of modified SBS and 0.1-0.5 part of a sulfur stabilizer, the modified SBS is prepared from the following components in parts by weight: 20 to 30 parts of SBS, 15 to 20 parts of propylene and 0.2 to 0.5 part of a Grubbs II catalyst; the preparation method of the SBS modified asphalt comprises the following steps: S1, heating and melting the matrix asphalt, adding the modified SBS into the matrix asphalt, uniformly mixing, heating, adding the sulfur stabilizer, and continuously stirring until the modified SBS is swelled and developed to obtain prefabricated asphalt; s2, carrying out constant-temperature heat preservation on the obtained prefabricated asphalt, and meanwhile, carrying out vibration homogenization, so as to finally prepare the SBS modified asphalt. According to the present invention, the blending ability of the modified SBS and