Stratospheric airship works in stratosphere about 20 km above ground. It can cruise or belocated in the air, and has become a good platform for reconnaissance, surveillance or track. Photoelectric system is an important equipment on the stratospheric airship. The advantage of remote sensing on stratospheric platform is introduced, especially on detectable distance. The components and principle are introduced according to the typical existing photoelectric systems. Furthermore, the key technique of photoelectric system for stratospheric airship is analyzed, and the design method is explained. This paper can be referenced for the design of such systems in the future.