Rectal cancer is one of the common gastrointestinal malignancies, and surgery is still the most important treatment for it. With the wide acceptance of the principle of total mesorectal resection and the clinical application of anastomosis, the anal preservation rate and survival rate of rectal cancer patients have been significantly improved. Urination and sexual dysfunction after rectal cancer surgery are still common complications and should be given sufficient attention in order to improve the quality of life of patients after surgery. At present, it is generally believed that the occurrence is mainly related to pelvic nerve injury. Clinically, the degree of urination and sexual dysfunction is often proportional to the extent of lymph node dissection in the pelvis. The causes of urinary dysfunction after rectal cancer surgery are: (1) direct injury to the nerves innervating the bladder after surgery; (2) posterior bladder emptiness after rectal resection, bladder displacement due to loss of support, resulting in bladder neck obstruction, causing urinary dysfunction; (3) traumatic, aseptic peri-cystitis. Disorders of urination caused by bladder displacement and peri-cystitis are transient and return to normal within 3 months. Long-term voiding disorders, however, are associated with more severe nerve damage. Causes of male sexual dysfunction after rectal cancer surgery: (1) Nerve injury: The somatic afferent fibers of erectile reflex arc are pubic nerves and the autonomic efferent fibers are pelvic nerve plexus. The pelvic nerve plexus is damaged during the process of cutting off the rectum and lateral ligaments during radical rectal cancer surgery, and the perineal surgical excision is too extensive and damages the pubic nerve, which may also lead to erectile dysfunction. The inferior abdominal nerve is centrally located and has a long path, so it is very easy to damage this nerve when performing parietal aortic dissection, leading to ejaculatory disorders. (2) Vascular injury and psychological factors may also cause postoperative sexual dysfunction. The key to the prevention of urination and sexual dysfunction after rectal cancer surgery is the scope of resection and the level of stripping. As long as the principles of total rectal mesenteric resection are strictly followed during surgery and the anterior sacral nerve, pelvic visceral nerve and pelvic plexus are not damaged, the incidence of urination and sexual dysfunction after surgery is extremely low. However, rectal cancer often has extra-cavity infiltration, and it is difficult to achieve the purpose of radical resection if the scope of peeling and resection is small.