衍射光栅实验是大学物理中的一个基础光学实验，可以用来测量光栅常数、光的波长等物理量.本文利用投影仪液晶屏替代衍射光栅实验中的光栅，通过设计一系列渐变的光栅图片并在液晶屏上显示，用线阵CCD测量相对光强与位置信息，与理论结果符合较好.实验装置成本低廉、理论简单、现象直观，可以作为理论课与实验课的光学演示装置. 

Diffraction grating experiment is a basic optical experiment in university physics, which can be used to measure grating constant, wavelength of light and other physical quantities. In this paper, the projector LCD screen is used to replace the grating in the diffraction grating experiment, by designing a series of gradient grating pictures and displaying them on the LCD screen, and measuring the relative light intensity and position information with a line array CCD, which is in good conformity with the theoretical results. The experimental device is inexpensive, simple in theory and intuitive in phenomena, and can be used as an optical demonstration device for theoretical and experimental classes.