The main reasons for bleeding after high anal fistula surgery are friction wound, wound infection, poor coagulation function of the patient, hanging thread detachment, surgical wound hemostasis is not complete and so on. 1. Stool friction wound: anal fistula surgery wound is generally not sutured, is open wound. When the patient stool, if the stool is hard and rough, rubbing the wound, it is easy to cause the wound to rupture and bleed. The amount of bleeding in this case is small. 2. Wound infection: when the wound is infected, it can lead to damage to the capillaries of the wound and rupture, thus bleeding. 3. Poor coagulation function of the patient: If the patient’s coagulation function is poor, the patient will also bleed after the surgery, and the amount of bleeding is larger in this case. 4. Hanging wire detachment: for patients with anal fistula with hanging wire therapy, there will also be bleeding when the hanging wire is detached. 5. Incomplete hemostasis of the surgical wound: in surgery, if hemostasis is not complete, patients can also have postoperative bleeding. In addition, if the action is rough in the process of postoperative drug change, it will also lead to bleeding. For high anal fistula surgery bleeding patients, should be as soon as possible to the hospital anorectal department, by professional doctors to check and give relevant treatment, to avoid delaying the aggravation of the condition and lead to adverse consequences.