Anal pain caused by anal fissure ulcer often causes severe pain and difficulty in healing is often caused by blood heat and intestinal dryness, constipation, excessive force in defecation, which ruptures the anal skin and develops repeatedly. Anal pain caused by anal fissure ulcers often occurs in the posterior and anterior middle of the anus, with the posterior part of the anus being the most common and the sides being less common. The fissure is linear or prismatic, and if the anus is opened, the fissured surface becomes round or oval. According to the clinical manifestations, anal pain caused by anal fissure ulcer should be distinguished from other diseases. 1.Anal fissure triad: It generally refers to anal papilloma or anal papillitis caused by anal fissure over time, sentinel hemorrhoid, old anal fissure or the three subcutaneous fistulas caused by it, and these three should belong to the category of stage III anal fissure in anal fissure. Therefore, the anal fissure triad is a stage III anal fissure. The fissures are old ulcers, combined with anal papillary hypertrophy and sentinel hemorrhoids, or accompanied by subcutaneous fistula and inflammation of the anal saphenous fossa, etc. 2. Severe anal pain: It is severe pain at the anus. This condition usually occurs during defecation, but it may also occur during non-defecation. It is mainly related to the following diseases: perianal abscess, internal hemorrhoid impaction, anal fissure, advanced anorectal cancer and anal foreign body.