If the anal fissure still hurts one month after surgery, it may be caused by postoperative infection, hemorrhoids, recurrence of anal fissure, constipation and other reasons. 1. Post-operative infection: anal fissure can be treated by surgical methods such as anal fissure resection, and if there is a secondary bacterial infection after surgery, it may cause anal fissure surgery one month and still hurt. 2. Hemorrhoids: Hemorrhoids formed by poor circulation around the anus may also lead to the symptom of anal fissure surgery one month still hurts. 3. Anal fissure recurrence: after anal fissure surgery, if there is a bad diet, it may lead to recurrence, which may also cause anal fissure surgery one month still hurts. 4. Constipation: Constipation caused by various reasons, dry stools can irritate the anus, which can also lead to anal fissure surgery one month still hurts. If the anal fissure still hurts one month later, there may be other reasons, so we suggest that the patient should go to the hospital for examination in time, and give the treatment as soon as possible with a clear diagnosis.