According to the technical requirements of Hangzhou Bay Bridge deck pavement for high-viscosity modified asphalt, a new type of high-viscosity modified asphalt was developed. By analyzing the base asphalt, SBS, the infrared spectra of chemical additives, on the basis of studying the microstructure changing laws of modified asphalt in modifying process, it is proposed to use the modified asphalt compatible design, which is SBS plus chemical reaction agent tackifier TW-1 and compatibilizer TW-2, so that the low-temperature ductility and elastic resilience of the modified asphalt are improved, at the same time, the dynamic viscosity of 60 ℃ is greatly enhanced, and the construction will not be affected. The high-viscosity modified asphalt has been successfully applied to Hangzhou Bay Bridge project.