Abstract: Due to the complex structure of the head unit for the panoramic ring optical system, the internal optical path is reflected and refracted for many times, which results in a serious condition of the stray light. Therefore, in the design process of the panoramic ring optical system, the analysis of the stray light is very important. The form of the stray light of the head unit for the panoramic ring optical system was analyzed, and the mathematical model of the stray light elimination was established for the stray light which was not reflected by the head unit of the panoramic ring optical system. On this basis, the panoramic ring optical system was optimally designed. The stray light reflected by the head unit cementing surface of the panoramic ring optical system was suppressed by a meniscus adhesive mirror with convex image surface, and modeled as well as simulated by the ASAP software. The simulation results show that the stray light energy is reduced by 90%, which proves that the adopted form and the mathematical model of the stray light elimination can effectively suppress the generation of the stray light.