Long-playing large-scale monitoring and small-target tracking can be implemented by the photoelectric detection system based on unmanned airship, which is particularly suited to momentous task, such as earthquake relief or flood succor. An enhanced photoelectric detection system based on unmanned airship is designed by using the two-axis, double-frame structure and three closed-loop control methods combined with dual GPS information. The whole system design is described in detail, including the system structure, function, control method as well as hardware and software. Moreover, the correctness and reliability of the system are verified by the system test and flight experiments.