ObjectiveTo investigate the clinical and pathological characteristics of advanced colorectal adenomatous polyps. MethodsPatients with colorectal adenomatous polyps diagnosed after colonoscopy in the Division of Gastroenterology of Zigong First People’s Hospital from January 2013 to March 2019 were selected. The patients were divided into advanced colorectal adenomatous polyps group (advanced group) and non advanced colorectal adenomatous polyps group (non advanced group), to analyze the location distribution, pathological type and the relationship with carcinogenesis of advanced colorectal adenomatous polyps. Results A total of 1 555 patients were included. There were 223 cases (14.34%) in the advanced group and 1 332 cases (85.66%) in the non advanced group. There was no significant difference in the distribution of canceration in postoperative pathological examination (P=1.000), but there was significant difference in other indexes between the two groups (P<0.05). The detection rate of high-grade intraepithelial neoplasia in the advanced group was higher in tubular adenoma than that in villous-tubular adenoma (41.18% vs. 13.74%; χ2=18.959, P<0.001). There was no significant difference in the detection rate of high-grade intraepithelial neoplasia between tubular adenoma and villous adenoma (41.18% vs. 25.00%; χ2=1.992, P=0.220). In the advanced group, 40 cases (17.94%) were at the right colon and 183 cases (82.06%) at the left colon. In the detection rate of high-grade intraepithelial neoplasia in the left colon, there was no significant difference between villous adenoma and villous-tubular adenoma (17.65% vs. 14.41%; χ2=2.801, P=0.094) or tubular adenoma (17.65% vs. 41.82%; χ2=3.289, P=0.088); the rate in tubular adenoma was higher than that in villous-tubular adenoma (41.82% vs. 14.41%; χ2=9.322, P=0.002). There was no significant difference in the detection rate of canceration among tubular adenoma, villous-tubular adenoma and villous adenoma in the advanced group (χ2=3.002, P=0.249). Conclusions At present, colorectal adenomatous polyps should be paid attention to. Endoscopic physicians should master the clinical and pathological characteristics of advanced colorectal adenomatous polyps, in order to raise the detection efficiency of advanced adenoma polyps and cancerous cases.