光學薄膜的鍍製，最迫切的為得到穩定的光學特性，即希望在蒸鍍完成後立即知道薄膜的光學常數。本文研究的主要目的，即在於撰寫計算光學常數的應用程式，供鍍膜工程師們能夠快速的分析。本文採用C + + Builder 5.0程式語言做為程式開發之工具。 本文研究之方法，主要係以光學薄膜穿透率之監控圖為藍圖，以波包之方法所發展而得。本研究具體的提出以三次 Spline 雲形線為基礎的曲線密合之方法並視基板為有限厚度，考慮基板兩側多重的反射與透射之效應，可輕易的得到具相當精確度之膜層折射率與消光係數之波形。 To get the correct optical constants of the coated films immediately after coating is very important for coating process . The major purpose of this research is to write a computer program to calculate the optical constants , and the computer program can enable coating engineers to analysis the result of the coating quickly . Here I adopt the program language of C++ Builder 5.0 to develop the computer program of coating. The main way of this research is using the monitoring curve as a database , and then developed from the curve fitting to computer program . The text not only specifies the method on the basis of cubic spline curve fitting , but also regards the substrate as finite , at the same time consider the effect of two-sided of the substrate in which multiple reflection and transmission take place . This program makes it easy to get the precise profile of the refractive index and extinction coefficient of the thin film .