在对椭圆偏振测量的基本原理进行了简单介绍和推导后，讨论了椭圆偏振测量中椭偏参数关于薄膜参数的灵敏度以及入射角对椭偏参数的影响，并进行了具体的仿真分析,得到如下结论：椭偏参数Delta对薄膜光学常数和薄膜厚度变化的灵敏度明显高于椭偏参数Psi。在椭偏数据处理中，椭偏参数Delta的测量精度直接影响薄膜光学常数和薄膜厚度的拟合精度。为了提高椭偏参数Delta的测量精度，可以选择入射角在膺布儒斯特角附近。所得结论对高精度椭偏测量具有指导意义。

Based on a brief introduction of the basic principle of ellipsometry and some derivations, the sensitivity of ellipsometric parameters with respect to film parameters and the influence of incident angle on the ellipsometric parameters were discussed, and its simulation analysis was made. It shows that the sensitivity of ellipsometric parameter Delta to the film optical constants and film thickness is apparently higher than another ellipsometric parameter Psi, and the measurement accuracy of ellipsometric parameter Delta directly affects the fitting accuracy of film optical constants and film thickness in the ellipsometric data processing. A method is provided to improve the measurement accuracy of Delta by choosing the incident angle close to the Pseudo-Brewster Angle.