Objective  This study aims to investigate the relationship between anastomosis location and anal function in low rectal cancer anus preservation operation.

  Methods  We chose 82 cases from patients who underwent rectal cancer anus preservation operation between January 2008 and November 2011. The cases were divided into five groups based on the anastomosis location, the distance between the anastomosis location, and the anal edge with L replaced: Group Ⅰ: L≤3 cm, Group Ⅱ: 3 cm < L≤4 cm, Group Ⅲ: 4 cm < L≤5 cm, Group Ⅳ: 5 cm < L≤6 cm, Group Ⅴ: below the peritoneum L>6 cm. The anal function of the patient before and after the operation was assessed using objective and subjective standards. The control group was set as well (descending colon and sigmoid colon cancer surgery patients who did not undergo pelvic floor and anus department operation).

  Results  Based on the Anorectal Manometry methods, the following conclusion can be drawn: Groups Ⅰ to Ⅲ have obvious anal function damage at the early postoperative period (3 months). After a year of repair and defecation exercises, Group Ⅰ still have anal function damage. Each index of group Ⅴ was close to the normal level three months after the operation. The following conclusions were also drawn based on the Xu ZhongFa anus function methods: obvious anal function damage are as follows: Groups Ⅰ-Ⅲ; Group Ⅲ can partially restore the anal function six months after the operation. Group Ⅱ can partially restore the anal function one year after the operation; and Group I still has anal function damage one year after the operation.

  Conclusion  Skilled surgeons operate on the premise that strictly follows the anus preservation operation indications by using the appropriate procedure. The anal function of patients with rectal cancer whose distance between anastomosis location and anal edge was above 3 cm can be preserved through one year of repair and defecation exercises after the operation. Moreover, the anal function of those whose distances between anastomosis location and anal edge were more than 5 cm to 6 cm can be recovered three months after the operation.