The sequelae of anal fistula should refer to the postoperative complications after anal fistula surgery. Anal fistula, as a common anal disease, is basically caused by anal gland infection, which develops from perianal abscess and must be treated surgically after diagnosis. The most common and serious complications after anal fistula surgery are anal stenosis and anal incontinence. The reason for anal stenosis and anal incontinence is that the condition of anal fistula is heavy and the surgery damages the internal and external anal sphincter and other perianal muscles more, resulting in post-operative damage to the control of bowel function, and the patient develops anal stenosis and anal incontinence. It is recommended to visit the anorectal department of a regular hospital, have the surgery performed by an experienced anorectal surgeon, and actively exercise the anal function after surgery so that complications can be minimized.