基于光栅衍射的转角法无需转动光管，与传统的转角法相比具有较高的测量效率。而微透镜阵列元件子单元数众多，利用该方法进行测量时，光栅的各级衍射斑可能发生干扰，影响测量精度甚至无法进行测量。利用Matlab软件模拟分析测量过程中子单元光栅0级和±1级衍射光斑间的干扰，通过分析测量光源波长、光栅周期、微透镜阵列的子孔径和焦距，选取合理的测量光源和光栅避免干扰，从而完成对微透镜阵列焦距的测量。测量结果表明，该方法具有较高的测量精度和测量效率，可用于单元数较多、F数较小的微透镜阵列焦距测量。

Compared with the traditional rotational method, a method for the focal length measurement of microlens array based on grating diffraction has a higher efficiency, because this method need not rotate the collimator. As microlens array has a large number of cells generally, the disturbance diffracted from nearby cells also needs analysis. The interferences between 0-order and ±1-order diffracted focula of grating are analyzed by Matlab. The proper wavelength and grating can be determined for different kinds of microlens array by analyzing the wavelength, grating period, sub-aperture and focal length of microlens array. The disturbance can be avoided and the focal length measuring of microlens array can be finished. The experimental results show that this method is fit for the testing of microlens array with small F-number and many cells because of its high precision and efficiency.