介绍了子孔径拼接检测平面波前的基本原理，提出了基于均化误差和最小二乘法的多个子孔径同时拼接的数据处理方法，有效减小了误差传递和积累。用该方法对Zemax 仿真的望远镜光学系统进行了子孔径拼接检测，拼接光学系统波前和直接用Zemax 得到的全孔径波前对比，其峰谷值(PV)和均方根(RMS)的偏差分别为0.015 1λ和0.001 6λ。并用口径为100 mm 的小口径干涉仪对口径为200 mm 的平面镜进行了拼接实验，将其全孔径波前与直接检测的结果对比，其峰谷值(PV)和均方根(RMS)的偏差分别为0.055 9λ和0.000 4λ。实验结果表明了该算法的有效性，该方法不仅适用于检测光学元件，也适用于对光学系统平面波前检测。

The principle of stitching interferometry for testing the flat wavefront was introduced. Error averaging method was used in the experimental data processing, which could reduce error accumulation and improve the precision. Based on the algorithm, we carried out experiments, tested the telescope optical system simulated by Zemax software, and used 100 mm small aperture interferometer to measure the 200 mm flat mirror. Compared the stitching results with the directly measured full aperture, the Peak-to-valley (PV) and Root Mean Square (RMS) of the wavefront phase distribution residua are 0.015 1λ and 0.001 6λ, 0.055 9λ and 0.000 4λ respectively. It was proved that the model and method are not only accurate and feasible to test the optical mirrors, but also can be applied to test optical system.