Based on the double refraction principle of outgoing beam in the biprism,the displacement method for measuring the small angle of biprism is presented.The error of this method is also discussed.

利镜引起射光束向向偏折原理,提了一种位移法测量玻璃镜微小底角法,介绍了测量基本原理,讨论了测量误差.