The diffusion behaviors on asphalt interface of high percentage recycled asphalt pavement(RAP) under multi factor coupling conditions were quantitatively characterized using fluorescence microscopy(FM) and dynamic shear rheometer(DSR). The results show that the fluorescence images can identify the diffusion action between RAP asphalt and virgin asphalt, and the quantitative evaluation indexes of interaction average optical density(AOD), integral optical density(IOD) and image gray level(IGL) increase linearly with the rise of virgin asphalt content(w). Additionally, with the rise of heating temperature and asphalt grade, the quantitative evaluation indexes i.e. the diffusion speed(DS), the degree of blending(DOB) and energy quantity(Q) increase significantly, and the distribution of virgin asphalt content(w) in each layers reaching unanimity, leading to decrease of the discrete distribution coefficient(DDC). Moreover, the DS and DDC closely decrease exponentially with the extension of heating time, and the other indexes increase and tend to be stable finally, which show that the key to improve the diffusion action is in the early stage. Specifically, when the filler asphalt ratio is small, every 20℃ growth in heating temperature is accompanied by 50%120% increase in DS value, and the values of DS can be increased by 2,10 times respectively with the rise of virgin asphalt grade and regenerant content, while the attenuation range of DS can be decreased by 10%50%. The value of DOB can be increased by 23 times when regencration agent is added, and the effects of improvement of diffusion action are particularly obvious.