Screening for rectal cancer includes the following methods: 1. colonoscopy, which can observe the lesions and take pathology at the same time. Pathological examination is the gold standard, which can clearly diagnose rectal cancer; 2.Barium enema, when there is no colonoscopy condition or temporarily cannot do colonoscopy, barium enema can be performed, which can make diagnosis from imaging; 3.Checking tumor indicators through laboratory, especially tumor indicators such as carcinoembryonic antigen, which can facilitate diagnosis; 4.Other imaging examinations, including CT, MRI or PET-CT can be done when there is condition, which can further diagnose rectal cancer or other tumor diseases. Other imaging examinations, including CT, MRI or PET-CT, can further diagnose rectal cancer or other tumor diseases. The specific method should be chosen according to the equipment of each hospital and the patient’s physical condition; 5.Anal finger examination, the lower rectum can be touched or anoscopy can be done, and finally colonoscopy can be changed to take pathology to confirm the diagnosis.