With the development of society and the improvement of people’s living standard, the incidence of rectal cancer has been increasing year by year. According to the clinical data, in recent years, the incidence rate of rectal cancer has ranked the third among all malignant tumors in Beijing, Shanghai and other big cities. Therefore, the early detection and treatment of rectal cancer is attracting more and more attention. The causes of rectal cancer are as follows 1. Environmental factors: According to relevant data, 41 national and regional epidemiological surveys, the incidence of rectal cancer is related to the consumption of fat in food. Frequent consumption of red meat such as pig, cow and sheep has a greater risk of cancer than consumption of chicken and fish. The incidence of rectal cancer is low in countries and regions where high-fiber foods are often consumed. 2.Genetic factors: According to relevant data, 10% of rectal cancer is related to genetic factors. 3.High risk factors of rectal cancer include: rectal adenoma, rectal inflammatory bowel disease, rectal schistosomiasis can cause the development of rectal cancer. In addition, the incidence of rectal cancer 10 years after cholecystectomy is higher than the incidence without cholecystectomy.