Thermo-oxygen aging asphalt and thermal oxygen-ultraviolet aging asphalt were prepared. The double-layers diffusion model of virgin and aging asphalt was constructed. Through the simulation calculation of relative concentration and diffusion coefficient， verification of pull-off tensile test and fluorescence microscope test， the relationship of diffusion degree with temperature and four components was analyzed. The results show that the thermal oxygen-ultraviolet aging asphalt is more difficult to diffusion with the virgin asphalt， and the adhesion with the virgin asphalt is poor. In the range of 10 ℃ to 40 ℃， the virgin and aging asphalt can diffuse rapidly. When the temperature is over 40 ℃， the promoting effect of increasing temperature on diffusion gradually decreases. The decreasing rate of promoting effect is greater for the diffusion of thermal oxygen-ultraviolet asphalt and virgin asphalt. The diffusion coefficients of four components of asphalt from large to small are in the order： saturate>aromatic≥resin>asphaltene. After ultraviolet aging， the diffusion coefficients of the four components decrease. Among them， asphaltene declines most significantly.