The utility model relates to an orbit tackle capable of self locking under stress, which is composed of orbits, a tackle arranged on the orbits and a hook hinged at the lower part of the tackle, wherein the tackle body of the tackle comprises two movable arms transversely arranged in a shape like the Chinese character 'yi'; the upper surfaces of two external end heads of the movable arms are respectively adhered with a rubber pad; the central external ends of the two movable arms are respectively connected with a pulley, and the central internal ends are respectively hinged with both ends on the upper part of an upper opening frame; the upper opening of the frame is provided with a concave hollow cavity downwards, and an elastic body is arranged in the hollow cavity; the two internal ends of the movable arms are pressed on the elastic body in the hollow cavity of the frame. The elastic body is composed of a spring and a plunger connected to the spring; the two edges of the hollow cavity of the frame are raised, forming self locking spacing fulcrums. The utility model has simple structure and convenient operation, can be automatically locked without moving and prevent optionally sliding under stress, and can be extensively applied to the fields of architectural decoration curtains, medical dropping-bottle orbit hangers and other industries.