RTFOT aging tests at different aging time for four kinds of asphalt were carried out and the aging test data were fitted to dynamic equation. The aging parameters and aging equation of penetration, ductility, softening point and viscosity of different asphalts were determined. The grey relational theory was utilized to assess the anti aging performance of different asphalts setting the L and r of penetration, ductility, softening point and viscosity as assessment indicators. The results show that there are nonlinear relationship between penetration, softening point, ductility, viscosity and aging time; the aging rate reaches the peak at the beginning and becomes smaller as the variation of aging time; the aging process of asphalt can be described accurately by dynamic equation and parameters L and r can be a good characterization of aging degree and aging rate, and the sort of aging parameters of different asphalts and indicators is inconsistent. The sort of anti aging performance of four kinds of asphalt is determined with grey relational theory as following：indoor produced modified asphalt＞ matrix 90# asphalt＞finished modified asphalt＞matrix 70# asphalt.