Aiming at fundamental issues in the application of titanium dioxide on modified asphalt including dispersion and reaging performance effect on asphalt,an analysis was made of the dispersion stability of titanium dioxide in asphalt with scanning electron microscope and also the effect of titanium dioxide on the performance of asphalt by some lab tests including softening point, penetration and ductility tests.A research was then made into the effect on the reaging performance of modified asphalt by TFOT and ultraviolet radiation aging test. The results show that titanium dioxide can be effectively dispersed in the asphalt under highspeed shearing force and adding some dispersing agent can improve the dispersion ability; when the titanium dioxide content is 4%, the road performance of modified asphalt changes little, and the modified asphalt is of the best antiaging performance.