With the improvement of the surgical skills of rectal cancer preservation technology, the number of patients who need to undergo combined abdominal perineal resection for rectal cancer is gradually decreasing, and there are more and more patients with low anus preservation, so much so that some physicians claim that there is no forbidden area for low rectal cancer anus preservation, no matter what kind of low rectal cancer has to undergo anus preservation! In low rectal cancer surgery, the first principle is to ensure the radicality of the tumor, and any anus-preserving surgery at the expense of the radicality of the tumor is wrong, especially the bottom line of anus-preserving surgery for low rectal cancer is that the lower tumor margin should not be less than 2 cm; besides, preserving a functional anus is also an important principle of low anus-preserving surgery, and if the preserved anus is not functional, it is obviously meaningless to preserve anus; Therefore, any surgery that expands the indications for anal preservation is questionable, and it is obviously incorrect to have no rectal cancer that cannot be preserved. For low rectal cancer, there are several issues to be considered as follows: i. Preoperative evaluation is needed, and caution should be exercised for low anal preservation surgery for those with low sphincter function Preoperative anorectal manometry should be performed, and if conditions allow, it is better to perform fecal imaging. For patients who already have impaired anal sphincter function before surgery, low anal preservation surgery should not be performed, otherwise the defecation function will be poor after surgery. Second, we should try to protect the function of the sphincter and prevent excessive damage to the sphincter muscle during surgery. During surgery, we should try to reduce the actions that are damaging to the internal sphincter muscle such as dilatation, and studies have shown that if the anal function is reduced by at least 25% after surgery if the anus is dilated more than four fingers. In addition, when performing procedures such as ISR, try to preserve some of the internal sphincter. In a previous animal experimental study, we used internal sphincter folding to perform internal sphincter reconstruction after ISR with some effect, but further research is needed to see if it can be used in the clinic. Third, postoperative examination and assessment of anal function should be performed to deal with problems in time Poor anal function after low rectal cancer surgery is mainly related to the following reasons: decreased rectal volume, internal and external sphincter injury, lack of anal canal-rectal reflex function, pelvic floor muscle and nerve injury, and decreased rectal sensory function, so patients mainly show more frequent stools, a sense of urgency to defecate, unconscious leakage of stool, and in severe cases, they cannot control of gas and liquid stools, and in the most severe cases, they cannot control solid stools and need to use liners, etc. When these problems occur, timely treatment should be carried out: 1, dietary guidance: advise patients to eat high-protein, high-calorie, coarse fiber, easy to digest food, can be given a certain antidiarrheal agents, to be gradually stopped after the formation of stool, avoid eating spicy and stimulating, dry and hard, easy to produce gas food such as onion, garlic and soybean products, dairy products, etc.; 2, lifting anal exercise: lifting anal exercise is the easiest way, but the effect is not Biofeedback therapy: it is effective for 80% of post-operative rectal cancer patients with abnormal anal function, but it can be used repeatedly if it is stopped. For patients with severe anal incontinence and poor results of other treatments, stoma surgery can be considered.