In the process of reflecting,scattering and transmiting electromagnetic wave,earth targets can produce polarized characteristics which related to the nature themselves,therefore,detecting the objects' polarization information becomes a new method in remote sensing.Since polarized reflectance always goes with bidirectional reflectance,the polarized three-dimensional spatial distribution of the targets can be obtained by a polarimeter during detecting its bidirectional reflectance.From the point of view of multi-angle polarized remote sensing mechanism,the quantitative relation between polarized BRDF and BRDF was studied.And the experiment testified the equality of the reflectance of bidirectional reflect,polarized reflect of 45 degree and polarized reflect of mean value in the corresponding azimuth angle,zenith angle,and detection angle and detection channels in 2π space.