双光栅干涉位移传感器拥有量程大、精度高等优点。文中详细阐述了传感器的测量原理，并对此理论原理进行ZEMAX软件仿真。与此同时，基于角谱理论推导得到干涉场中的光强分布。结果表明，激光通过双光栅后可以得到三角函数分布的干涉条纹，且双光栅相对移动一个光栅距离时条纹相应移动一个周期。最后分析了对双光栅传感器位移测量结果可能带来误差的因素，以及这些因素对测量结果的影响，文中给出了部分因素的误差表达式。

The displacement sensor based on the principle of double diffraction grating interference has many advantages, such as the large measurement range, high accuracy and so on. The principle of this sensor is explained and simulated with ZEMAX. At the same time, the light intensity distribution in the interference field is studied based on the angular spectrum theory. The result shows that the trigonometric distribution interference fringes are gained after the laser passing the dual-grating, and the fringes move a cycle when the dual-grating moves one grating distance relatively. The factors which may result in the displacement measurements errors of dual-grating sensors and the effect of these factors on the results are studied. Error expressions of some factors are also presented.