Abstract: At present, most of the transmission and distribution lines in the power system are composed of overhead lines.During the construction and operation stages, operators need to wear safety belts to carry out high-altitude operations on the towers.In recent years, accidents caused by high-altitude falls by workers have occurred frequently, and how to effectively control the risks of high-altitude operations has become an urgent problem to be solved. Therefore, it is necessary to design a locking automatic alarm device for high-altitude safety belts, which can timely and effectively remind high-altitude workers to implement the protection of safety belts and meet the safety guarantee needs of high-altitude work.