In 1982, the pathologists of the National Colorectal Cancer Collaborative Group proposed a unified classification standard in China, which divided colorectal polyps into five categories: 1, neoplastic polyps (i.e., adenomas); 2, misshapen polyps; 3, inflammatory polyps; 4, septic polyps; 5, other types of polyps (e.g., mucosal hypertrophic redundancies). Colorectal adenomas are pathologically divided into tubular adenomas, villous adenomas and villous tubular adenomas, depending on the number of tubular and villous components. The new standard set by our pathologists is that those with 20%-80% of a particular component are of mixed type. According to Morson’s report, tubular adenomas are the most common of the three types, accounting for 75%, villous for 15.3%, and mixed for 29.7%. In the classification of colorectal adenomas, the early ones can be divided into four types: 1) small flat adenomas; 2) small depressed adenomas; 3) microscopic adenomas; and 4) “serrated” adenomas. Adenomas may be tipped or untipped in appearance. It is generally believed that colorectal cancer originates from adenomatous polyps, and removal can reduce the risk of colorectal cancer. The positive correlation between the incidence of adenomas and the incidence of colorectal cancer has been confirmed epidemiologically. As the incidence of colorectal cancer rises, the incidence of colorectal adenomas also rises, and as the incidence of colorectal cancer rises rapidly, the rate of adenoma detection also increases rapidly. The type of pathology correlates with carcinoma, with the most carcinomas occurring in the villous form and less in the tubular adenomas. The former has a cancer rate of 29%-40%. Adenoma carcinogenesis is a long chronic process, at least 5 years and an average of 10-15 years, which is consistent with the slow growth of benign adenomas.