日冕仪的工作特点决定了其对杂散光抑制要求极其严格。 根据反射式日冕仪的工作特点，通过分析其光学特性以及其抑制系统杂散光的基本原理，设计了反射式内掩日冕仪系统，其相应参数为视场0.67°、口径47 mm、焦距768 mm、系统总长1 200 mm，系统在30 lp/mm处的MTF值＞0.6，弥散斑半径＜2.5 μm，成像质量达到衍射极限。通过分析系统杂散光特点，建立了消杂散光结构，全部抑制了系统的主要杂散光源。杂散光抑制水平达10-6~10-8B⊙，可以实现对日冕的清晰成像观测。

The principle of coronagraph requires that stray light in coronagraph system must be kept at an extremely low level. Based on the principle of mirror coronagraph, a internally occulted mirror coronagraph is designed by analyzing its optical characters and the basic rules to suppress the stay light. This system with a FOV of 0.67°, a aperture of 47 mm, a focal length of 768 mm and a total length of 1 200 mm shows that its MTF value at 30 lp/mm is above 0.6, the radius of spot is less than 2.5 μm, and the image quality of the system approaches to the diffraction limit. In consideration of the character of stray light in the system, a structure of suppressing stray light is built, and the main sources of stray light are suppressed entirely by the designed structure. The system can achieve a level of 10-6~10-8B⊙ approximately in suppressing stray light, and it can get high quality coronal images.