As the name suggests, anorectal stenosis should first be divided into anal stenosis and rectal stenosis according to the site. Anal stenosis is caused by chronic inflammatory stimulation, surgical injury, congestion, edema, and scarring of the various layers of the rectal wall due to the proliferation of connective tissue and loss of elasticity. Stenosis is caused by elasticity. According to the classification of stenosis pattern, there are linear stenosis and tubular stenosis. Linear stenosis can be located in any part of the anorectum, in the form of a line, or a half-loop or a week, with a stenosis length of about 12.5 px; tubular stenosis is tubular, mostly located in the anorectum or rectum, with a smaller lumen, and the length can be 1~50 px. Classification according to the severity of the disease: 1. Mild stenosis: the symptoms are mild, mainly poor defecation, and the stool becomes thin. The index finger can pass through the anorectum during finger diagnosis, but the two index fingers cannot pass under anesthesia, accompanied by mild stool dyspareunia. 2.Moderate stenosis: the stenosis hole is about 25px, the operator has difficulty in passing the index finger, but the little finger can pass, there is obvious defecation dyspareunia, and the abdomen is distended. 3.Stenosis with an orifice diameter of 25px, the operator cannot pass the little finger, and some can only pass the tip of chopsticks, accompanied by severe systemic symptoms and symptoms of chronic colonic obstruction. Generally speaking, the lighter the stenosis, the easier it is to treat, and the heavier the stenosis, the more difficult it is to treat.