Fizeau 干涉仪由于具有参考光与测试光共光程的优点成为多数干涉仪采用的结构形式，对于干涉仪的结构及其影响因素在理论上已进行了较广泛的研究。但如何对Fizeau 干涉仪进行仿真是干涉仪检测所面临的问题。本文首先简要介绍Fizeau 干涉仪及相位解包裹的基本原理并利用Matlab 编写了基于矩形域的解包裹程序。然后利用Zemax 光学设计软件建立起Fizeau 干涉仪通用模型，利用四步相移法对干涉仪的面形检测进行仿真并利用编写的解包裹程序计算出待测面的面形。仿真面形检测结果与真实情况一致表明Fizeau 干涉仪通用模型能较好的对实际干涉仪面形检测进行仿真。

Fizeau interferometer with the advantage of common optical path which the reference light and test light are passed becomes main structure of interferometer. The structure of interferometer and its influencing factors in theory have been analyzed by lots of literature. But how to simulate Fizeau interferometer is the problem we faced. This article first introduces the basic principle of Fizeau interferometer and phase unwrapping, and the phase unwrapping procedures based on Matlab were written. Then Zemax optical design software was used to model Fizeau interferometer and four-step phase shifting was used to simulate surface testing. By the phase unwrapping procedures, the true surface to be tested were got. The simulation of testing result is in line with the result given by real Fizeau interferometer. Simulation result shows that the model can simulate the actual optical interference.