Hydrated lime content in asphalt mastic greatly influences the performances of asphalt mixture. The aim of this paper is to study the hydrated lime to the high temperature characters, resist ability of aging, together with workability. Asphalt mastic made with different content of hydrated lime was used in Dynamic Shear Rheological and Viscosity Tests. The optimum hydrated lime content was proposed in terms of test results above. The results illustrated that hydrated lime was an appropriate addition agent which can improve asphalt mastic properties greatly, however, too much hydrated lime may result in the decrease of asphalt mixture performances, substitution of 30% hydrated lime was proposed as an upper limit.