As usual an axially incident linearly polarized light beam reflected by a glass corner-cube reflector (OCR) will(become an elliptic polarized light. There are two particular azimuth angles. At these angles the linearly polarized light beam incident at the OCR will still be a linearly polarized light when it goes out of the OCR except that the plane of the beam polarization has been varied. In this paper we calculated these two paticular azimuth angles and the variations of the plane of the out-going beams. These results were proved experimentally.