For the general population, screening for colon cancer can be done starting at age 50. For high-risk groups, screening for colon cancer should be conducted from the age of 40. High-risk groups include: 1) people with poor diet and bad habits, including those who consume high protein, high fat and no meat for a long time, and those who smoke and drink alcohol for a long time; 2) people with family history of gastrointestinal malignant tumors, and those who have family history of gastrointestinal malignant tumors among their first-degree relatives need to be screened for colon cancer at the age of 40; 3) people with history of colon polyps, colon adenomas and inflammatory bowel disease. For people with a history of colon polyp, colon adenoma and inflammatory bowel disease, the above-mentioned diseases should be dealt with timely and correctly to prevent their malignant transformation into colon cancer.