横向剪切干涉技术是一种直接测量波面相位分布的光学测量方法，由于其不需要高精度的参考平面，并且能够测量偏离量较大的表面面形偏差，因此得到了更为广泛的应用。但是，通常情况下剪切量大小的选择凭工作经验来确定。为了给出一种定量的剪切量判定方法，论文提出了一种基于Zernike多项式拟合的剪切量判定方法，通过计算机仿真和实验给出了剪切量与测量误差的关系，发现剪切量为测量口径1/10时即可达到良好的测量结果。

Lateral shearing interferometry is an important optical measurement technology which obtains the wave-front phase distribution directly. Due to the ability of measuring surface shape of large deviation without high precision reference plane, it has been used in various fields;however, the selection of shearing displacement depends on work experience. In order to provide an explicit determination method, a shearing displacement determination method based on Zernike polynomial fitting is proposed, and the relation between shearing displacement and measurement error is given by computer simulation and experiment.