Colorectal cancer is a malignant tumor originating from colorectal mucosal epithelium, and is one of the most common malignant tumors in clinical practice. There are more than 250,000 new colorectal cancer cases and about 140,000 deaths each year in China, accounting for 20% of the new and death cases of colorectal cancer worldwide in the same period. The 5-year cancer-related survival rate for locally progressive colorectal cancer is 70%, and the 5-year survival rate for advanced colorectal cancer patients with distant metastases is only 12%, however, most early colorectal cancers can have a good prognosis with a 5-year survival rate of over 90%, and some of them can be cured through minimally invasive endoscopic treatment. The incidence and mortality rate of colorectal cancer show a rapid increase from the age of 40, and the risk of colorectal cancer is higher in men than in women. Screening targets for colorectal cancer in China: those who meet any of the 1 and 2-3 should be listed as high-risk groups for colorectal cancer, and are recommended as screening targets: 1. age 50-75, male or female, 2. positive fecal occult blood test 3. previous colorectal adenomatous polyps; ulcerative colitis, Crohn’s disease and other precancerous diseases.