Colonoscopy includes e-colonoscopy and e-anoscopy. e-colonoscopy is not a non-examination of the anus, when the e-colonoscope lens enters the anal intestinal cavity, the field of view of its lens has crossed the part of the anus where the local hemorrhoids grow and crossed the dentate line, so e-colonoscopy does not have a clear diagnostic significance for local lesions around the anus, especially those localized above and below the dentate line. If colon lesions are suspected, you can choose e-colonoscopy, and if rectal lesions are suspected, you can choose e-colonoscopy or e-proctosigmoidoscopy. And the lesions of rectum and anal canal need to be combined with anal finger diagnosis and perianal ultrasound examination. The main purpose of e-colonoscopy is to check and exclude the presence of inflammation and organic lesions in the colon and rectal cavity.