The colonoscope consists of a thin, bendable light-guiding fiber tube that can be delivered through the anus into the rectum and travels retrograde along the intestine to the end of the ileum via the sigmoid colon, descending colon, splenic flexure, transverse colon, hepatic flexure, ascending colon, and cecum. According to the imaging and image transmission structure can be divided into fiberoptic colonoscopy and e-colonoscopy. Colonoscopy can observe the whole colon and even the end of ileum completely and clearly, and take photos and videos of suspicious parts as well as biopsies for pathological examination, which can make timely and accurate diagnosis of the disease. In addition to assisting in diagnosis, colonoscopy can also be used to insert instruments through the colonoscopy biopsy hole for effective treatment of lesions, such as laser treatment of early cancer, electrocoagulation of polyps, electrical resection, laser treatment, and local bleeding medication to stop bleeding. When hemorrhoid patients have both hemorrhoids and rectal and colonic tumors, it is easy to neglect the examination of rectal and colonic tumors due to the discovery of hemorrhoids, which leads to delay in the diagnosis and treatment of rectal and colonic tumors. Therefore, colonoscopy is needed for patients with symptoms such as blood in stool, especially if the cause of blood in stool is unclear and the color of blood is not fresh. Colonoscopy is also important for the screening of colorectal cancer. The incidence of colorectal cancer is higher in patients over 50 years old with anal disease, and colonoscopy is more meaningful for these patients.