Most anal fistulas are caused by perirectal anal canal abscesses, which may form when a perianal abscess breaks down. Perianal abscess, or abscess around the rectum and anal canal, is caused by purulent germs that cause obstruction and infection of the anal glands to form abscesses. And anal fistula is a granulomatous tube around the anal canal or rectum, which is mainly composed of three parts: internal opening, fistula, and external opening. Most of the anal fistula caused by perianal abscess, when the abscess breaks down or surgical incision and drainage of the formation of the external port, located in the perianal skin, when the pus is fully drained or cleared, the pus cavity is gradually shrinking, due to the fast growth of the external port, the abscess is often false healing, resulting in recurrent episodes of abscess breakage or incision, the formation of multiple fistulas and external port. In addition, the perianal abscess will not necessarily develop into an anal fistula, it may just be a stage after the maturation of the abscess, it is recommended that the patient timely medical examination, clear condition after targeted treatment, pay attention to personal hygiene, keep the perianal area clean and dry, and follow the doctor’s instructions for regular review.