考虑了波带片在离焦和非单色光照明条件下的光斑特性。通过数值计算，得到了在不同离焦量时光强分布曲线、光斑大小、以及特定范围内总能量随离焦量的变化；同时得到不同带宽的光强分布曲线、光斑半径随带宽的变化曲线。并研究了用于软Ｘ光扫描显微镜的聚焦波带片允许的离焦误差以及光斑半径与带宽的关系。 The spot characteristics of the zone plate under defocused and non-monochromatic illumination are considered. Through the numerical calculation, the light intensity distribution curve, the spot size and the total energy with the defocus amount in different defocus amount were obtained. At the same time, the light intensity distribution curve with different bandwidth and the curve of spot radius with the bandwidth were obtained. The defocusing error and the relationship between the spot radius and the bandwidth of the focused zone plate used in the soft X-ray scanning microscope were studied.