入射角、基底玻璃折射率、膜介质折射率、膜厚等因素会影响单层介质膜保偏全反射直角三棱镜的保偏特性，且各因素的影响程度并不相同。本文分析了上述各因素的微小变化对保偏特性的影响，并提出了选择膜介质的方法 The incident angle, the refractive index of the base glass, the refractive index of the film medium, the thickness of the film and other factors will affect the polarization maintaining properties of the single-layer dielectric film with the polarization-preserving total reflection right-angle prism, and the influence degree of each factor is not the same. This paper analyzes the impact of these small changes of the above factors on the polarization maintaining characteristics and proposes a method of selecting the membrane medium