Abstract: In view of problems that current standard safety pins of mine car use manual operation when bolting and pulling and cannot realize automatic uncoupling, a new type of safety pin used in trip of mine car was designed. Structure, working principle, installation and characteristics of the safety pin were introduced, and design of automatic uncoupling and pulling system taking the safety pin as core was given. The actual application shows that the safety pin meets with actual application requirements of simple structure, reliable self-locking, easy to pull, low cost and less modification for structure of mine car.