通过对粗糙表面散射情况的分析发现，普通金属材料的表面散射能量主要集中在10°散射角内。针对这种现象，提出了基于该散射特性的光学系统外遮光罩设计方法，该遮光罩的杂散光抑制角比基于反射理论计算的大5°，具有良好的散射杂散光的抑制作用。最后以Ritchey-Chirtien(R-C)光学系统为例，为其设计了合适的遮光罩，并在TracePro软件中对比性地建模、分析。结果证明了该模型的正确性，且该遮光罩对抑制杂散光起到了很好的效果，点源透射比(PST)相对较低。

By the analysis of the scattering situation of the rough surface, it is found that the ordinary metal material scattering energy is centralized in 10°. Based on the scattering characteristics, the method of the outer baffle design is put forward, the baffle rings′ restraint angle is 5° larger than the stray light suppression angle which is calculated based on reflection theory, and the effect of the outer baffle to suppress the stray light is very good. The baffle is designed for a Ritchey-Chirtien (R-C) system and the model is built in the TracePro software for analysis. With the contrast of different models and the designs, the results show that the consideration of the scattering is more accurate, the effect of the outer baffle is better, and the point source transmittance (PST) of the system is lower than others.