In recent years,the incidence of colorectal polyps and colorectal carcinoma showed a trend to increase gradually. Statistical analysis demonstrated that 80% of colorectal carcinoma were developed from colorectal adenoma,and adenomatous polyps accounted for 1 / 2-1 / 3 of colorectal polyps. Endoscopy is the golden standard for examining intestinal lesions,yet it is not completely correct and certain missed diagnosis has occurred. Factors causing missed diagnosis of colonoscopy include lesion factors and non-lesion factors. This article reviewed the advances in studies on missed diagnosis of intestinal polyps and related factors in colonoscopic examination.