为了更好地利用偏光显微镜检测光通过透明光学晶体材料后偏振态的变化，研究和鉴定晶体的光学特性，从介绍偏光显微镜的光学结构入手，分析了自然光通过偏光显微镜的几何光路，然后利用Stocks参量和Muller矩阵分析自然光通过偏光显微镜的偏振态变换，从理论上给出了出射光偏振态变化的原理，并利用计算机模拟了光强随各参数的变化曲线，分析了干涉图像形成的过程。对在实践中使用偏光显微镜测量晶体薄片的双折射率、延长符号、分析材料的光学特性以及观察材料的结构更具有指导性的意义。

In order to investigate the polarization state variation of the light passing through transparent optical crystals and to evaluate the optical characteristics of crystals with polarizing microscope,the optical structure of the polarizing microscope was introduced,the geometrical optical path which natural light went through in the polarizing microscope was analyzed,and the polarization state transformation happened when the natural light passed through the polarizing microscope was investigated with Stokes parameters and Muller matrix. The principle of polarization state transformation was given theoretically. The theoretical fundamentals are provided for operating the polarizing microscope and understanding its operation principle.