The invention discloses a hook-clasp structure and underwear back clasp, which belongs to the technical field of underwear accessories, comprising a clasp hole and a hook, one end of the clasp hole is provided with a positioning ring, the other end of the clasp hole is provided with a step clasp position, one end of the hook is provided with a positioning ring, the other end of the hook is provided with a hook portion, the step clasp position protrudes away from the bottom surface of the positioning ring of the clasp hole, the hook is clasped on the step clasp position through the hook portion, so as to be clasped with the clasp hole, a step clasp position protruding away from the back surface of the
human body is provided on the clasp hole, so that a space clearance is formed between the step clasp position and the back surface of the
human body, and when the hook is clasped on the step clasp position through the hook portion, the front end of the hook portion is placed in the space clearance without contacting the back surface of the
human body, thereby effectively avoiding the hook portion from pressing the back surface of the human body to bring discomfort to the human body, and compared with the prior art, the overall wearing comfort is better, meanwhile, since the step clasp position protrudes away from the bottom surface of the positioning ring of the clasp hole, the hook portion of the hook is able to be more conveniently clasped into the step clasp position when worn.