The morphological characteristics of colorectal polyp surface were observed under high-definition non-magnifying colonoscopy and studied against pathological histological diagnosis to evaluate the predictive ability of polyp mucosal surface morphological characteristics on the pathological type of colorectal polyps. Methods A total of 330 polyp-like lesions of 142 colorectal polyps were examined by high-definition colonoscopy and observed the mucosal glandular duct opening pattern, and the capillary pattern (CP) of mucosal surface was observed by narrow band imaging (NBI), and its sensitivity, specificity and accuracy were determined by comparison with the pathological findings of polyps. The sensitivity, specificity and accuracy of NBI were 88.2%, 83.6%, 95.5%, 64.4%, 87.3%, 5.4, and 0.1 for the positive and negative predictive values. High-definition non-magnifying colonoscopy with close observation combined with NBI imaging of polyp surface morphology is valuable for identifying colorectal polyps as tumorigenic and non-tumorigenic, and has a good compliance rate with pathological diagnosis, which helps to decide further treatment and follow-up plan.