In order to achieve azimuth accurate measurement of polarizer axis in the polarization signal generating unit, a device and its working principle were introduced with the use of magneto-optical modulation, right-angled prism and autocollimator to elicit the axis azimuth, and the ordinary polarization prism problems were pointed out. A new type of polarization device was designed based on Glan-Taylor prism to solve this problem, it uses three calcite crystals with identical material composition, each side can form a Glan-Taylor prism respectively with the middle, that it can be a analyzer when it is turned 180° around; the working principle of the device and installation and ways of working were described in detail, that the new component can eliminate the prism manufacture and installation errors in the work process was analyzed, it can complete polarizer axis azimuth determination. Finally, experiment results verify that the angle measurement precision of the device is 0.5″, and the system has characteristics of high stability, precision and operability, and so on.