为了测量向列相液晶的双折射率，根据等厚干涉原理，设计了一种劈尖测量方法。通过调整劈尖的方向实现了o光(寻常光)和e光(非寻常光)转换，通过观测空气和液晶界面条纹数目之比，分别测定了o光和e光的折射率。结果表明，本方法简单方便，可以避免很多因素对测量结果的影响，误差可控。

In order to Measure the Birefringence of nematic Liquid Crystal, a wedge method was proposed according to the principle of fringes of equal thickness. The ordianry light (o light) and the extraordinary light (e light) were achieved by switching direction of the wedge, and the number of fringes on both sides of air and liquid crystal were counted to determine the refraction index of o light and e light.respectively. The result inicated that the approach was simple, convenient and avoiding the influence of many factors with error under control.