为解决移相干涉仪(PSI)测量平板类光学元件面形过程中产生多表面干涉条纹混叠的问题，介绍了基于波长移相的多表面干涉条纹分析方法的基本原理。对三表面干涉测量进行仿真分析，通过对随时间变化的干涉图进行傅里叶变换，提取相应频谱级次的相位，可求得前后表面面形分布。比较了不同取样帧数及不同干涉光频谱变化范围下的误差最大值与方差的变化。与原始仿真面形比较，在理想情况下，该方法测得面形误差优于10－4λ。采用该方法对一实验元件的三表面干涉图进行分析计算，并与Zygo干涉仪测量值比较，结果表明，元件面形峰谷值（PV）与均方根值(RMS)相对误差均低于1%。

To solve the multiple-surface interference fringe pattern admixture problem in measuring parallel plate with phase-shifting interfermetry (PSI), the basic principle of multiple-surface interference fringe analysis method with wavelength-tuning phase-shifting is introduced. As the three surfaces interference for example, the front and back surfaces can be got by analyzing the interferograms by Fourier transform and getting the phase of the corresponding spectrum. The maximum error and variance distributions with different sampling buckets and light spectral ranges are compared. In ideal case, the error of this method is lower than 10-4λ. Experiments on an optical element by this method and Zygo′s interferometer, the result shows that the relative errors of surface peak-to-valley (PV) and root mean square (RMS) is lower than 1%.