The anal part of the contraction on the pain, may be due to hemorrhoids, anal fissure, anal sinusitis and other diseases caused by the cause. 1. hemorrhoids: if you suffer from hemorrhoidal diseases due to a long time failed to get effective treatment, it is likely to lead to hemorrhoidal swelling prolapse, causing secondary infection, or the formation of thrombosed external hemorrhoids, may cause anal contraction pain, may also be accompanied by itching, pain around the anus, bleeding during defecation and other symptoms. 2. Anal fissure: this disease is usually caused by long-term constipation, anal trauma or anal tumor, which can lead to cracks in the skin layer of the anal canal area under the dentate line, in this case, the anal contraction will form a stimulus to the cracked skin, which will cause pain, and may be accompanied by constipation, bleeding and other symptoms. 3. Sinusitis: the disease is usually due to long-term constipation caused by the anal sinus area for a long time accumulation of stool, easy to cause secretion blockage, resulting in the sinus area infection, causing inflammatory reaction, under the stimulation of inflammation, may lead to the local mucous membrane of the sinus ulceration, resulting in the pain of anal contraction, may also be accompanied by anal itching, defecation and other symptoms. Anal contraction pain, may also be caused by other reasons, if the symptoms continue to be unable to alleviate, should be taken seriously, as soon as possible to see a doctor, diagnose the cause of the disease, to give targeted treatment, to avoid causing delays in the condition.