In order to distinguish the scattered light generated by the three defects of micro-particles, sub-surface and micro-roughness existing above the super smooth surface, and to obtain the best region for detecting these three scattering mechanisms, combined the Bidirectional Reflectance Distribution Function (BRDF) with Jones matrix and the polarization coefficients of the three defects were given in the four polarization states ss, sp, ps, pp. On this basis, the relationship between the three defects and scattering azimuth in four polarization states was simulated and analyzed. The results show that these defects could be distinguished by using p-polarized scattering light induced by p-polarized incident light. According to the different relations between the three defects and the variation of scattering azimuth, the best area to distinguish three kinds of defects and its realization methods were given.