：杂散光分析是提高信噪比，保证测量精度的关键手段之一。依据星载大气主要温室气体监测仪光学系统结构及其工作特点，设计了仪器的外遮光罩和前置望远系统的遮光筒。建立仪器的三维实体模型，利用Tracepro软件对仪器氧气通道(758~768 nm)的杂散光进行了分析，给出系统杂散光点源透射比(PST,Point Source Transmittance)曲线， PST在30°离轴角小于5×10-7。依据PST拟合曲线，通过积分计算得到杂散光系数小于4%。结果表明：杂散光抑制措施效果明显，杂散光水平达到了设计指标要求。

Stray light analysis in optical system is a key means to improve the signal to noise ratio and ensure the measurement accuracy. Based on the optical system structure and working mode of space-borne spatial heterodyne spectrometer for monitoring greenhouse gases, the outer and inner light shield was designed. With the Tracepro model, the stray light of oxygen channel(758-768 nm) in the system was simulated and evaluated, then (PST,Point Source Transmittance)of the system was calculated, PST values were less than 5×10-7 at the offaxial angle of 30°, and the stray light coefficient was less than 4%. The obtained PST value and the stray light coefficient shows that the light baffle and other mechanisms have suppressed the stray light effectively, and the stray light suppressing level of the system satisfied the requirement of design.