In order to assessing applicability of SBS modified asphalt used in rigid-flexible composite pavement interlayer,4%SBS modified asphalt prepared using SK-70 # as original asphalt, according to SHRP criterion, high temperature performance, fatigue performance and construction viscosity of SBS modified asphalt are tested by the dynamic shear rheological apparatus and brookfield viscometer. Tests got that high temperature PG grade of original sample and short-term aging respectively is PG76 and PG70, fatigue design temperature is 28℃, 60℃ viscos...