The main differences between colonoscopy and anoscopy are as follows: 1. The length and scope of investigation are different: colonoscopy is longer and can reach the entire colorectum, with a length of 1-1.5m, while the scope of anoscopy is in the range of 10-20cm, mainly for the rectum and a section of the anal canal to examine the intestines. For more than sigmoid colon, if you want to diagnose the lesion, you must go through colorectal microscopy for further examination; 2. There is a difference in operation: colonoscopy often requires specific operation by doctors in gastrointestinal endoscopy centers, while anoscopy can be performed by general surgeons or anorectal surgeons for simple operation, which is convenient, effective and fast.