Colonoscopy is generally not a substitute for anoscopy. Colonoscopy and anoscopy have their own scope of application and cannot replace each other. Colonoscopy can check colon tumor, intestinal inflammation, colorectal polyps and other diseases, but also can clarify the cause and location of lower gastrointestinal bleeding. While anoscopy is mainly to check the anal canal as well as rectal lesions, such as sinusitis, rectal polyps, internal hemorrhoids, anal papillae hypertrophy, proctitis and so on. Anoscopy is more suitable for examining diseases near the anal canal, and anoscopy is simpler and easier to perform than colonoscopy. Enteroscopy is more suitable for checking diseases such as total colon or rectal lesions. Therefore, colonoscopy is not a substitute for anoscopy, and different ranges of diseases need to be examined according to the doctor’s recommendations.