The mechanism of PPH treatment of prolapsed hemorrhoids: Longo believes that: (1), PPH ring-type excision of 2~3cm mucosa and submucosal tissues of the lower end of the rectum, restoring the normal anatomical structure, i.e., the anal cushion is back in place. (2), the excision of submucosal tissue, blocking the blood supply of the superior hemorrhoidal artery to the hemorrhoidal area, postoperative hemorrhoidal body atrophy. Intraoperative precautions: 1, the purse-string suture should be at least 2CM on the tooth line, the distance is too far so that the anal cushion suspension is not sufficient, postoperative hemorrhoidal retraction is incomplete; less than 2CM postoperative pain increases. 2, hemorrhoidal prolapse patients, the tooth line downward, and expanding the anus extrusion, identification difficulties. Can also be anal margin as a sign, in the anal margin above the 4~6CM at the purse-string suture. 3, purse-string suture should be continuous, leaving no obvious gap. If the suture is too shallow, the mucous membrane will tear off, or the gap is too wide, it will easily lead to incomplete anastomosis and affect the postoperative recovery. When tightening the anastomosis, the longitudinal axis of the anastomosis must be consistent with the rectum, otherwise it is easy to damage the intestinal wall. After tightening, reconfirm that the purse-string suture is correct, and the mucosa is completely into the nail warehouse. 5, female patients also need to vaginal palpation, check whether the vaginal wall of the whole layer into the nail warehouse, in order to prevent damage. Superiority of PPH compared with traditional surgery: short operation time, mild postoperative pain, fast recovery and fewer complications.