1. People with high-risk factors need to be vigilant The United States is a country with a well-controlled incidence rate of bowel cancer. According to the survey, the early diagnosis rate exceeds 25% (less than 15% in China) due to the vigorous popularization of colonoscopy in the United States. Therefore, for the above-mentioned high-risk groups with family history of intestinal cancer and intestinal cancer diseases, including patients with long-term symptoms such as bloody stools, they need regular medical checkups and prefer effective and reliable colonoscopy for timely detection of colorectal lesions, so as not to delay treatment. 2, reasonable diet structure, need to ensure that life should reduce fatty foods, pickled and smoked food and fried food, in addition to the above-mentioned fatty foods can produce bile acid, pickled food contains carcinogenic nitrosamines and high protein food fried to produce heterocyclic amines are carcinogenic. Fish, lean meat and low-fat dairy products should be used instead of high-fat meat, boiled and steamed food instead of fried food, and more easily digestible food with high vegetable protein, high vitamin and low fat, especially fresh fruits and vegetables rich in vitamin A and C and cereals rich in fiber, which can regulate the acid-base balance in the body. 3, good lifestyle needs to be developed, first of all, need to develop good bowel habits, especially need to be alert to the elderly constipation, because the intestinal cavity stay between too long between the toxins produced by the feces, will persistently stimulate the intestinal wall. The key to improving constipation is to drink more water, exercise more, maintain a good diet, eat more fiber-based foods, consume honey and yogurt appropriately, and reduce the use of herbs such as rhubarb and aloe vera to aid in bowel movements. In addition, harmful substances produced by smoking may also induce colorectal cancer. We suggest that people in good health should include colonoscopy in their medical checkups after the age of 50. At present, rectal cancer accounts for 60% of all intestinal cancers in China, and 70% of them are low rectal cancers, which can be initially diagnosed by simple anal examination, but most people, especially middle-aged people, refuse or even resist anal examination. It can be seen that it is crucial to cultivate the correct awareness of medical examination.