The methods for examining rectal cancer are as follows: 1. Physical examination: including visual examination and palpation of the abdomen to check whether there is a lump in the abdomen; more than 90% of patients with right hemicolectomy can palpate the lump; 2. Rectal finger examination: this method is very simple, easy and economical, and more than 80% of patients with rectal cancer in China can be found by rectal finger examination, and patients can also palpate higher parts of the tumor by adopting the left side lying position. During the examination, we need to understand the location, shape, size and extent of the mass in the intestinal perimeter, the activity of the base, whether the intestinal cavity is narrowed or not, and whether the lesion has invaded the neighboring organs, etc.; 3.Auxiliary examination: including endoscopy, 70%-75% of colorectal cancer is located within 25cm from the anal verge, and the lesion can be observed by sigmoidoscopy, and colorectal cancer above 25cm can be examined by fiberoptic colonoscopy. The endoscopy can also be used for photography, biopsy, brush examination and smear for pathological cytological examination; 4. Other examinations: X-ray examination, barium enema X-ray examination, abdominal CT, abdominal ultrasound, etc. X-ray examination and barium enema X-ray examination are necessary examination methods for tumors above the middle part of the sigmoid colon, which can detect constant filling, defect, mucosal destruction, intestinal wall stiffness, luminal narrowing, etc. It can also detect multiple colon cancer, and the positive rate can reach more than 90%.