As the existing evaluation index of viscoelastic properties of asphalt is inapplicable to modified asphalt, the viscoelastic properties of both base asphah and modified asphalt are analyzed by using the dynamic mechanical method. In the investigation, the parameters describing the viscoelastic properties at different temperatures and fre- quencies are measured, and the variation laws of both Han curves and dynamic viscoelastic parameters are analyzed. The results indicate that the temperature dependence of Han curves of modified asphalt varies at different temperatures, that there exists a great difference in viscoelasitc properties between base asphalt and modified as- phalt due to the complex morphological structure of modified asphalt, and that the dynamic mechanical analysis is effective in revealing the relativity between the macroscopic mechanical properties and the microstructure of modified asphalt.