The invention provides a high-viscosity and high-elasticity modified asphalt, which is prepared from the following raw materials in parts by weight: 100 parts of matrix asphalt, 6.5 to 9.5 parts of SBS graft copolymer, 0.5 to 2 parts of tackifying resin, 0.1 to 0.35 part of antioxidant, 0.2 to 1.5 parts of vulcanizing agent and 0.1 to 1.0 part of compatibilizer rubber oil. The invention also provides a preparation method and application of the high-viscosity and high-elasticity modified asphalt. The high-viscosity and high-elasticity modified asphalt provided by the invention has the advantages of having good high temperature stability, low temperature crack resistance and anti-aging performance, replacing the expensive imported high-viscosity modified asphalt without affecting the use performance of pavement, and reducing the engineering cost, and can be widely applied to paving of domestic high-performance pavements.