The invention discloses a hoop structure which comprises an inner hoop, a strap and a regulating rod, wherein the inner hoop is fixedly connected to the strap; the regulating rod passes through the two ends of the strap; and the two ends of the regulating rod are provided with reverse threads connected to the two ends of the strap. In this way, the two ends of the strap are limited by the reverse threads, and therefore, the hoop does not generate size transform according to size of a clamped object; when the regulating rod rotates to regulate the hoop, expansion stress and locking stress are symmetrical, and therefore, the hoop structure is stable in structure and is good in stress; during the regulation, the two sides simultaneously move, so that the speed is regulated conveniently, and the use is convenient.