The paper introduced the effect and principium of Sagtital focusing double crystal monochromator ,and described measurement for positon of facula from Sagtital focusing double crystal monochromator.

• 简要介绍了弧矢聚焦双晶单色器的作用及基本原理,描述了离线测量弧矢聚焦双晶单色器出射光斑位置的方法。