The easiest way to diagnose rectal cancer is rectal finger test. Clinically, most of the patients who have unexplained blood in stool for a long time or are highly suspected of rectal cancer can have a preliminary diagnosis of rectal cancer through rectal fingerprinting. In the process of fingerprinting, an uneven and hard mass can be found in the rectal area, and patients with middle and advanced stage can be diagnosed with pus and blood in stool, which can be used to diagnose the cancer of the lower part of the rectum effectively. However, finger prick cannot be the final diagnosis, and it is necessary to cooperate with colonoscopy, pathological tissue biopsy and other examinations to make the final diagnosis according to the final results.