In the past 30 years, the incidence of colorectal cancer in China has been increasing year by year. Among colorectal cancers, rectal cancer accounts for about 85%. In some rectal cancer patients, the anus needs to be removed together with the rectal cancer when it is removed. After the anus is removed, the stool is rerouted and discharged through the abdominal stoma. This surgery is called: combined abdominal perineal rectal cancer resection, also known as Mile’s surgery. The disadvantages of this surgery are obvious: abdominal colostomy causes great inconvenience to the patient’s life and also brings great psychological burden to the patient. Patients are often reluctant to go out of their homes and participate in social activities. In recent years, with the progress of science and technology, especially the new understanding of the biological characteristics of rectal cancer, the anus-preserving surgery for low rectal cancer not only has theoretical basis, but also practical operation is feasible. Anal preservation surgery for low rectal cancer has been carried out in some large medical centers. Some patients with colorectal cancer have avoided anal resection. Basic research on rectal cancer: the lymph node spread of rectal cancer is mainly upward, especially above the peritoneal fold rarely spreads to the side and below. The rectum was cut 2 cm below the lesion, and no cancer infiltration was found at the cut edge. This is the theoretical basis of anus-preserving surgery for low rectal cancer. Therefore, it is reasonable and safe to cut off the rectum from 2 cm below the tumor. Application of anastomosis: For rectal cancer located within 5 cm from the lower end of the tumor according to the anal margin, it is very difficult and unsafe to use manual suturing. With the application of anastomosis, the rectum can be cut off in the deep part of the pelvic cavity, and intestinal anastomosis can be performed to complete the anus-preserving surgery for low rectal cancer. Improvement of surgeon’s level: Experienced anorectal surgeons can fully free the rectum in the pelvic cavity up to the pelvic floor muscles with the help of electric knife, ultrasonic knife and other surgical instruments. And the rectum can be dragged out from the anus, cut off between the inner and outer rectal sphincter, and then anastomose the colon with the anal canal with an anastomosis to achieve extreme anal preservation. In conclusion, due to the understanding of biological behavior of rectal cancer, the improvement of surgical skills, and the improvement of surgical instruments, more and more anal preservation surgeries are applied in clinical practice, and some patients avoid removal of the anus, which improves the quality of life of patients and brings good news to the majority of rectal cancer patients.