Abstract: The organic bentonite was used to modify the asphalt for pavement. According to the road test results of organic bentonite modified bitumen, the SEM and DSC methods were further used to investigate the mechanism of modified bitumen by analyzing the difference of the dispersing state and DSC atlas when organic bentonite, SBS and SBR were used as modifiers in bitumen. The relationship between the mechanism and the performance was also discussed. The result showed that there had good consistency between organic bentonite and asphalt, where organic bentonite was uniformly dispersed in the asphalt and crosslinking happened, making the colloform texture and components in asphalt change. Thus the macroscopic road performance of asphalt is enhanced.