A fecal fistula is an abnormal passage between the genital organs and the intestine. The most common type of fistula in obstetrics and gynecology is the rectovaginal fistula. The cause of fecal fistula is complex, diverse and prone to postoperative infection and high recurrence rate. The following are the postoperative preventive measures for transvaginal discharge during stool dilution: 1. Careful separation and operation during surgery to prevent the occurrence of transvaginal discharge during stool dilution. Injury of surgery and anastomosis of the vagina during low rectal cancer surgery is an important reason for the occurrence of transvaginal discharge of stool, so minimizing intraoperative injury is an important aspect. 2. If vaginal injury is found after anastomosis, the anastomosis needs to be excised and the conjunctival anastomosis is performed again. After performing the anastomosis, the anastomotic ring should be carefully checked for vaginal wall tissue. The author applies gentian violet to the posterior vaginal wall after vaginal preparation before performing low rectal surgery, which can be easily detected once the vaginal wall is accidentally injured during the operation due to the anastomosis or the closure. In addition, a vaginal examination can be performed and if there is a vaginal injury, it can be clearly felt as if there are adhesions between the rectum and the vagina, which is something to be aware of and consider that there may be a vaginal injury. 3. In case of postoperative occurrence of loose stool when passing through the vagina, it is necessary to choose interposition of labia majora fascial flap or interposition of thin femoral muscle. If there is no intraoperative rectal injury and the stool passes vaginally after surgery, we usually use a transperineal stoma and then wait for it to heal on its own, in fact, the rate of self-healing of rectovaginal fistula is low after simply performing a transperineal stoma. 4. If the use of interposition surgery fails, transabdominal fistula excision and coloanal drag-out anastomosis are required. If the interposition surgery fails, transabdominal fistula resection and coloanal drag-out anastomosis are required. The procedure is traumatic, difficult and has many surgical complications, but the postoperative results are better and the success rate can reach more than 90%.