The electromagnetic wave scattering from a dielectric dihedral structure is discussed in this paper. In order to measure the scattering mechanism, we measured a scattering from a brick by using a polarimetric GB-SAR system. And we found three scattering characteristics of the dielectric dihedral structure. Especially, separated scattering at the center of the target in HV component and penetration of electromagnetic wave in VV component may be used to extract information of a target. Then, we validated a scattering from a concrete block at different azimuth angles and detected the dependency of the azimuth angles by evaluating the polarization orientation angle based on circular polarization basis. Therefore, the polarimetric GB-SAR can validate the scattering mechanism of buildings by using dielectric dihedral object like a concrete block.