Abstract: Objective To retrospectively analyze the factors of polypus cancerization in large intestine, and to discuss the importance of total colonoscopy for colorectal cancer and colorectal polypus patients.Methods The endoscopic and pathologic features of colorectal cancer and colorectal polypus patients with bowel polyps detected by video colonoscope were retrospectively reviewed and analyzed.Results Of these 1100 cases, 1543 polyps were found in 387 patients.42 cases were found to have cancerization.Villous adenomatous polyps in the left colon, ≥2.0cm in diameter are liable to cancerization.Most colorectal cancers originated from the rectum or simgmoid colon, The broader the pedicles and the larger the diameters of polyps are, the higher the malignant rates could be.Of these 1100 cases, 326 colorectal cancers(29.63%)were detected.The age tend to suffer from colorectal cancer and colorectal polypus patients、polypus cancaration are similar higher than 45.92 cases of colorectal cancers were found to have concurrent colorectal polyps.Multiple primary colorectal carcinoma was observed in 29 cases.66 patients who have had colorectal cancer operation were detected to have colorectal polyps.Conclusion Many factors, such as patient′s age, the size, morphology, pathology pattern and location of the polyp, were related to colorectal cancerization.Total colonoscopy helps diagnose colorectal cancer, reduce the rate of misdiagnosis and improve the survival.