1.Minimally invasive Laparoscopic rectal cancer anal preservation surgery is to use the poking hole in the abdomen to extend the surgical instruments into the abdominal cavity, so that there is no need to make a long incision in the abdomen, no incision or small incision in the abdomen, so that the patient’s pain is obviously reduced and recovery is fast. 2.Curative The resection range of bowel segment in open rectal cancer surgery is the same as the abdominal incision, as the saying goes, how big the incision is can open how big the surgery is. In open rectal cancer anal preservation surgery, sometimes doctors take a conservative attitude and do not make the incision too big for fear of slow recovery of patients, and the resection range of intestinal segments may sometimes be insufficient. In contrast, the resection range of bowel segment in laparoscopic rectal cancer surgery is not limited by the abdominal incision. If the laparoscopic rectal cancer anal preservation surgery mastered the technique of colon splenic flexure or left hemicolectomy free, it is completely possible to: remove the middle and lower 1/3 intestinal canal of sigmoid colon with 2 cm wide base of sigmoid colon mesentery and rectal mesentery, that is, 10-15 cm above the tumor and 2-5 cm below the tumor, which is in line with the principle of rectal cancer radical treatment. 3.Cosmetic Open rectal cancer anus-preserving surgery, in order to fully reveal, generally make a mid-abdominal incision about 20-30 cm long, and it is impossible to consider cosmetic. Laparoscopic rectal cancer anal preservation surgery sometimes requires a 5-6 cm long incision in the abdomen in order to remove the specimen, and this 5-6 cm long incision can be made in a slightly curved incision in the lower abdomen according to the direction of the skin, which is in line with the characteristics of cosmetic surgery. 4.fragmentation Open rectal cancer anal preservation surgery is performed from incision into the abdomen, freeing, resection of specimen, intestinal reconstruction, placement of drainage tube and closing the abdomen. Everything is carried out under direct vision, and the whole operation is completed in one go. In contrast, laparoscopic anal preservation surgery requires poking a hole in the abdominal wall, freeing, resecting the specimen, reconstructing the intestine, and placing a drainage tube. With the exception of laparoscopic modified Bacon or laparoscopic trans-sphincteric proctocolectomy, laparoscopic double anastomosis for rectal cancer is performed under a monitor for the majority of the time, often with a small 5- to 6-cm-long incision in the abdomen, and some of the surgical operations are performed under direct vision, such as removal of the specimen or placement of the mushroom head of the anastomosis. The whole operation is sometimes supervised on the monitor and sometimes operated under direct vision, which appears to be a fragmented operation. Whether it is open rectal cancer anal preservation surgery or laparoscopic rectal cancer anal preservation surgery, the principles of surgery are the same, such as the principles of tumor-free and sterile must be followed; intestinal reconstruction needs good blood supply and tension-free principles, etc.