Three months after anal fistula surgery, there is pus at the incision, which may be due to wound infection, perianal abscess, anal fistula recurrence. 1. Wound infection: after anal fistula surgery, due to the special location, postoperative wound exposure, if the wound care is not allowed, it may cause wound infection. Due to the repeated stimulation of inflammatory factors will cause the wound area skin redness, swelling, slow healing and pus and other symptoms. 2. Perianal abscess: After the anal fistula surgery, it may cause the perianal tissue to be attacked by bacteria, inducing perianal abscess. It will cause the patient to have swelling and pain around the anus, and when the symptoms are serious, there will be pus, fever and other symptoms. 3. anal fistula recurrence: anal fistula surgery three months after the incision of pus, may also be due to anal fistula in the operation, not clean or potential fistula still exists, there is the possibility of recurrence, resulting in postoperative incision of pus. Patients after anal fistula surgery, once the body discomfort or abnormal phenomenon, we must consult a doctor in time to diagnose and clarify the cause of the treatment as soon as possible, to avoid delaying the condition.