Anal swelling is one of the difficult anorectal diseases, it is not an independent disease, but a symptom caused by several systemic diseases. Patients often feel unbearable anal swelling, sometimes radiating to the lumbosacral, buttocks and thighs, which may be accompanied by urgency and heaviness, frequent bowel movements. Often episodes of repeated delay, light for a few days, or months and years, difficult to cure, seriously affecting the patient’s quality of life. Clinical cause of anal swelling of common diseases are 1, internal hemorrhoid inflammation and edema or embedded: internal hemorrhoid surface mucous membrane erosion, edema, bleeding and a large number of submucosal thrombosis, severe cases can be out of the anus, out of the hemorrhoidal nucleus embedded in the outside, sudden for embedded hemorrhoids. Patients are accompanied by a strong sense of anal swelling, patients with embedded hemorrhoids will also have severe pain, requiring immediate treatment. 2, rectal mucosal prolapse: can also be called “prolapse of the anus”, as the name suggests, is the organization inside the anus off to the outside of the anus. However, what we are talking about here is “rectal mucosa prolapse”, the rectal mucosa is loosely piled up in the rectum, but has not yet come out of the anus, which can cause anal swelling and defecation feeling. 3, proctitis: if chronic colitis involves the rectum, there can be a feeling of anal distension and increased bowel movements. The general course of the disease is long, recurrent, and the degree of disease varies. 4, perianal abscess: acute onset, and easy to misdiagnose. Due to the deep location of some abscesses, lesions occur in the area of plant nerve innervation, pain is often not obvious, manifested as swelling, cramps or rectal irritation. 5.Sinusitis: In addition, the inflammation of sinus and anal valve is also called anal cryptitis, which can further develop into perianal abscess, which is the most common cause of anal swelling. Rectal cancer: Rectal cancer is more hidden, and it is hard to be found in time at the early stage. Patients will have symptoms such as anal swelling, increased frequency of defecation and feeling of incomplete defecation, etc. They should be alerted, examined and treated in time.