Commonly used examination methods for rectal cancer include rectal fingerprinting, proctoscopy, barium enema, CT, MRI, and tumor markers. Rectal diagnosis is the simplest, convenient and harmless examination, which can be done at any time in outpatient clinic. Rectoscopy or colonoscopy biopsy can be used to confirm the diagnosis, barium enema can see the tumor morphology, but can not take biopsy.CT and MRI provide diagnosis of rectal cancer imaging, which helps clinicians to analyze the condition, and is helpful in determining the treatment plan.