为了突破大口径反射镜面形检测的瓶颈，提出了子孔径拼接干涉检验方法。分析研究了子孔径拼接的基本原理与实现流程。基于三角剖分算法、最小二乘拟合和齐次坐标变换等建立了综合优化子孔径拼接数学模型。结合工程实际，规划7个子孔径完成了口径为800 mm的大口径碳化硅反射镜的拼接测量，获得了全口径面形分布。利用基准靶标并基于迭代算法实现了镜面物理坐标与拼接像素坐标之间的转换，从而为大口径反射镜后续数控精确加工提供了依据。

In order to overcome the difficulty of testing the surface shape of large mirror, the subaperture stitching interferometry (SSI) is introduced. The basic principle and flow chart of SSI are analyzed, the synthetical optimization stitching model and effective stitching algorithm are established based on triangulation algorithm, least-squares fitting and homogeneous coordinates transformation etc. With engineering examples, a large sic mirror with the aperture of 800 mm is tested by SSI with 7 subapertures. The coordinate transformation between digital controlled fine processing the mirror surface and pixel coordinate is fulfiled by bench mark and iterative algorithm, so it provide the basis for the subsequent the physical coordinate of the large mirror.