从光程函数出发， 研究了平面变栅距光栅的聚焦及消像差原理， 并据此设计了用于软 Ｘ射线波段的变栅距光栅。用光线追迹程序对所设计的变栅距光栅进行了性能模拟计算。结果表明， 此光栅具有良好的聚焦性能。 Based on the optical path function, the principle of focusing and eliminating aberration of planar variable pitch grating is studied, and a variable pitch grating for soft X-ray waveband is designed. The raytracing program was used to simulate the performance of the variable grating. The results show that the grating has good focusing performance.