In recent years, the incidence and mortality rate of colorectal cancer in China are increasing, and in life, many people do not know much about colorectal cancer. Colorectal cancer, also known as colorectal cancer, including colon cancer and rectal cancer, is a common malignant tumor, and its incidence rate is rising. The newly published 2015 China Tumor Annual Report shows that colorectal cancer has ranked third in the incidence of malignant tumors and fourth in the mortality rate in urban areas. The occurrence of colorectal cancer is a multifactorial and multi-stage process, which is the result of the interaction between the internal factors of the human body and the external factors of the environment. Epidemiological studies show that environmental factors account for 80% of the high risk factors for rectal cancer, mainly related to high fat, high calorie, low fiber diet and lack of physical activity, and some colorectal cancers are closely related to genetics.