In order to adapt the portable DTF-6 sun-photometer to the wild harsh environment, and to achieve outdoor long-term automatic unmanned measurements, development of automatic protection system for DTF-6 sun photometer is necessary. From the system’s overall control scheme, mechanical design, microcontroller automatic control system design, PC software design are introduced here. In the automatic protection mode, DTF-6 sun-tracking movements and the water-resistant automatic control system are simulated more than once. The results of experiments show that the system can achieve 24-hour sun-photometer automatic measurement and protection, which has a certain rationality and reliability.