There is some quantitative relationship between polarized reflection and bidirectional reflection. In this study, the specular reflection and diffuse reflection components were computed by measuring the polarized reflection of granite surfaces that were different in roughness, And then it was quantitatively analysed how the roughness of granite surface influenced the two kinds of components in hotspot and non-hotspot. Meanwhile, through the analysis, it was found that incidence angle would influence the components, and this kind of influence was controled by the roughness of the granite surface.