Trans-abdominal portion：First，the splenic flexure is mobilized by using cephalic and medial approach，and the root of inferior mesenteric vein is ligated and cut off；second，the lymphatic adipose tissue at the root of the inferior mesenteric artery is dissected by using medial approach，retaining left colonic artery outside the sheath；Third，according to the TME principle，the rectum is separated until the endpoint of abdominal separation. Transanal portion：Depending on tumor height，a purse-string is placed distal to the tumour either under direct vision or laparoscope. The rectal wall is full thickness and perpendicularly transected circumferentially after marking the dissection line. According to the “posterior-anterior-lateral” sequence，circumferential dissection was performed in a down-to-up manner，and prevent injuries of neurovascular bundles and pelvic nerves. When transanal dissection reaches the peritoneal cavity，the specimen is extracted transanally. The anvil was tied into the proximal bowel using a purse-string suture and a second purse-string suture was placed on the rectal stump transanally. Then anorectal anastomosis is performed under direct vision.