Objective To develop a scoring system for estimating advanced colorectal neoplasm risk in average-risk population in southern Jiangsu province, and to evaluate its screening efficiency. Methods An average-risk population of colorectal neoplasm in southern Jiangsu province, who underwent colonoscopy, was included in this study. All participants were asked to complete a questionnaire on demographic characteristics, medical history, smoking, alcohol consumption, dietary intake, and other factors that may be associated with advanced neoplasms. A multivariable logistic regression method was used to identify independent predictors of advanced neoplasms. A scoring system was developed from the logistic regression model by using a regression coefficient-based scoring method, and then was internally validated. The screening efficiency of the scoring system was assessed by its calibration, discrimination, and accuracy. Results A total of 905 average-risk participants were included in this study. The scoring system comprised 5 variables (age, sex, coronary artery disease, egg intake, and defecation frequency), with scores ranging from 0 to 10. The system had good calibration (P=0.205) and good discrimination (area under the receiver operating characteristic curve = 0.75, 95% confidence interval: 0.69-0.82). If score 2.5 was used as the screening cut-off value, the sensitivity, specificity, accuracy rate, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio were 93.8%, 47.6%, 50.1%, 9.1%, 99.3%, 1.79, and 0.13, respectively. Among the participants with low-risk (0-2) or high-risk (>2) scores, the risks of advanced neoplasms were 0.7% and 9.1% (P<0.001), respectively. If colonoscopy was used only for persons with high risk, 93.8% of persons with advanced neoplasms would be detected while the number of colonoscopies would be reduced by 45.4%. Conclusion The scoring system in this study has satisfactory screening efficiency and can be used for preliminary screening of advanced colorectal neoplasms in average-risk population in southern Jiangsu Province.