Statistics show that the incidence of colon and rectal cancer in China has increased by 31.95% in urban areas and 8.5% in rural areas. Although some cancer-causing and cancer-promoting factors of colorectal cancer have been discovered, there are no mature preventive measures for the causes, so health education and “early detection, early diagnosis and early treatment” are still important strategies for the prevention and treatment of colorectal cancer. Etiological prevention At present, the etiology of colon and rectal cancer is not yet clear, but the high-risk factors for its development have been studied more deeply. In the past 20 years, a large number of epidemiological studies have confirmed that colorectal cancer is the result of the synergistic effect of environment, diet, living habits and genetic factors, which is caused by the action of carcinogens combined with cytogenetic factors leading to the gradual development of cancer through genetic mutations. The risk factors for the development of colon and rectal cancer are mainly focused on diet, genetics and lifestyle, and are also related to stool habits, stool weight and stool passage time. The average daily stool weight is negatively correlated with the risk of colon and rectal cancer; eating more fiber-rich foods, such as fresh vegetables and fruits; taking proper supplements of trace elements calcium and selenium, and proper physical activity are also protective factors for colon and rectal cancer; the likelihood of colon and rectal cancer is four times higher for those who work at rest and take little physical exercise than those who are more active and take part in physical exercise regularly. Obesity is a risk factor for colorectal cancer, and men who are severely overweight have a higher incidence of colorectal cancer; those who have a body mass index (height2/weight) of more than 23 are at high risk of developing colorectal cancer. Genetic factors play an important role in the development of colorectal cancer. Hereditary non-polyposis colon cancer (HNPCC) and familial adenomatous polyposis (FAP), both of which are clearly autosomal dominant diseases, are closely related to heredity in 5-20% of colon and rectal cancers. Among the first-degree relatives of patients with colon and rectal cancer, the heritability of colon and rectal cancer was (16.78+ or -6.20)%, which was 1.68 times higher than that of the healthy population without family history of colon and rectal cancer.