Regularity of elliptical polarized motion by turning the stage of an ore microscope is investigated, and variation in outer rectangle of the ellitical pola- riled light is analysed. Formulae for motion track of major axis of the ellipse are obtained in the case of phase-difference being 0º，90º and 180ºrespectively. Motion track of the major axis of an ellipse is drawn in the range of phase difference from 0º to 45º，and rotation angle of the stage corresponding to the largest apparent angle of rotation (Ar) is analysed.