静止轨道(GEO)成像系统外遮光罩设计是空间载荷设计的重要组成部分。根据成像系统所处的空间杂散环境特点，通过分析不同太阳遮蔽角对外遮光罩几何结构的影响，确定了合适的遮光罩高度-直径比；研究了不同离轴角下刀口式和蜂窝式结构对杂光抑制能力的差别，Tracepro软件仿真结果表明，在相同的遮蔽角下前者比后者抑制能力高5%~28%。在此基础上，利用黑体腔工作原理，设计实现了一种新型二级遮光罩。最后结合某静止轨道成像系统进行仿真验证。结果表明，在太阳遮蔽角处，外遮光罩点源透射率(PST)曲线值小于10-8，杂光抑制效果好，同时很好地解决了单级遮光罩内边缘效应问题，满足工程应用要求。

Baffle design is an important part of geostationary earth orbit (GEO) imaging system design engineering. According to characteristic of space stray radiation environment, the influence of the varied sun shading angle to the baffle′s structure is analyzed, and height-diameter ratio is discussed. Then, the difference of stray light suppression between bladed and honeycombed structure is studied in different off-axis angles, and the Tracepro simulation results show that the bladed one has a better performance of suppression than honeycombed one with improvement from 5% to 28%. Moreover, referred to the works of blackbody, an improved two-stage baffle is obtained, and an example of baffle design of GEO imaging system is cited. It is indicated that the point source transmittance (PST) curve is less than 10-8 at sun shading angle, and the problem of diffraction effects in inner edge of single-stage structure is removed. The new structure is better in stray light suppression and satisfies the engineering application requirements.