Colorectal cancer examination methods are as follows: 1. the gold standard is colonoscopy; 2. stool occult blood test, under normal circumstances, the intestinal mucosa is bright and neat, the red blood cells in capillaries will not leak out, once the red blood cells in capillaries leak out, it means there is a breakage somewhere and there is a possibility of potential colorectal cancer; 3. stool tumor gene test; 4. barium enema angiography, colorectal cancer can be examined by barium angiography; 5. CT examination can find colorectal cancer with certain volume and size. The main diagnostic method or means of colorectal cancer is colonoscopy, which can realize the whole colon examination from the anus to the junction of small intestine and biopsy when suspicious lesions are found, and the diagnosis can be confirmed once cancer cells are found.