Intestinal polyps are divided into inflammatory polyps and adenomatous polyps, among which adenomatous polyps are precancerous lesions. the reasons for considering adenomatous polyps as precancerous lesions are as follows. 1. residual adenomatous tissue can be seen around some colon and rectal cancer lesions. 2. the site of colorectal cancer is consistent with the preferred site of adenomas. 3. the occurrence of colorectal cancer can be prevented if adenomas are removed. 4. family The occurrence of colorectal cancer is likely to occur in familial intestinal polyp lesions. Adenomatous polyps are divided into villous adenomatous polyps, tubular adenomatous polyps and mixed polyps, while the cancer rate of tubular adenomatous polyps is about 10%-20%, and the cancer rate of villous adenomatous polyps is up to 50% or more, and mixed polyps are in between. In general, the cancer rate of single small polyps is low, while the cancer rate of multiple polyps with increased volume is high, and the cancer rate of multiple polyps is significantly higher than that of single polyps.