薄膜科学与技术是当前高科技中的一个重要领域，用反射式椭偏仪测量薄膜厚度是一个重要的物理实验．然而，目前的实验内容只能确定膜厚在第一周期以内的值而不能确定膜厚的周期数，因而不能测得薄膜的实际厚度．本文讨论了这一问题并提供了一个简易可行的解决办法 Thin film science and technology is an important field in current high technology. It is an important physical experiment to measure the film thickness by reflection ellipsometry. However, the current experimental contents can only determine the value of the film thickness within the first cycle but can not determine the number of cycles of the film thickness. Therefore, the actual thickness of the film can not be measured. This article discusses this issue and provides a simple, workaround solution