The performance of 70# petroleum asphalt, SBS modified asphalt and high modulus modified asphalt were studied. The effects of high modulus agents on the viscoelastic properties of asphalt of different dosages were quantitatively studied through rheological test. The influence of high modulus agent on viscoelastic properties of asphalt was also compared with SBS modified asphalt, and the modification mechanism of high modulus agent was studied by fluorescence microscopy. Based on rutting test and dynamic modulus test, the differences in road performance between high modulus modified asphalt mixture and SBS modified asphalt mixture were compared. The results show that the high modulus agent has good effect in improving the high temperature performance and viscoelastic properties of the virgin asphalt. When the dosage reaches 667%, the modification effect is better than that of SBS modified asphalt. The high modulus agent particles can swell in the asphalt to form polymer links that improve the viscoelastic properties of the asphalt. The high modulus modified asphalt mixture has better resistance to deformation than the SBS modified asphalt mixture, and has superior performance in high temperature areas.