Objective: To understand the prevalence and risk factors for functional constipation (FC) among high school students in Chongming District of Shanghai. Methods: A cross sectional study was conducted in Chongming District of Shanghai from March-June 2019. A total of 4 969 adolescents under the age of 18 were recruited high schools, using a stratified random sampling technique. A validated self administered questionnaire on Rome IV criteria for diagnosing FC and predisposing factors was filled by each student in a classroom setting. Results: The prevalence of FC among middle school students in Chongming District of Shanghai was 13.95%. There were no significant differences in the prevalence between males and females, middle and high school groups, and urban and rural areas( P ＞0.05). In senior high schools, students in the graduation year were more likely to suffer from FC(17.36%，130/749) than other students (13.77%，201/1 460)( χ 2=5.01, P =0.03). The prevalence of FC in the key senior high schools(18.23%，115/631) was significantly higher than that in ordinary high schools (13.07%，49/375)( χ 2=7.43, P =0.02). Multivariate Logistic regression analysis showed that frequency of physical exercise, and consumption of spicy foods, proportion of spicy foods in the diet, consumption of vegetables, a lower proportion of vegetables in the diet, drinking water, anorexia, quality of sleep and school type were associated with FC in high school students ( OR=0.11-7.71, P <0.05). Conclusion FC is prevalent among high school students on Chongming District of Shanghai, especially among middle school graduates, and many risk factors were significantly associated with the occurrence of FC.