Objective: To understand the prevalence and associated factors of functional constipation(FC) among primary and middle school students in Shaanxi Province, in order to provide a basis for preventing FC in students. Methods: A stratified cluster random sampling method was used to conduct a questionnaire survey on 9 133 primary and middle school students aged 10-18 in eight primary and secondary schools in Shaanxi Province from March to September,2017. Chi square test and multivariate Logistic regression were used to analyze the associated factors of FC among primary and middle school students in Shaanxi Province. Results: There were a total of 364 students meeting the FC Rome IV diagnostic criteria, with a prevalence rate of 3.99%. Among them, there were 155 male students with a prevalence rate of 3.43%, and 209 female students with a prevalence rate of 4.53%. Univariate analysis showed that gender, breastfeeding, separation from parents, long term school meals, types of staple foods, breakfast frequency, cold foods eating frequency, spicy foods eating frequency, fried food eating frequency, pickled food eating frequency, desserts eating frequency, vegetables eating frequency were related to FC, and the differences were statistically significant ( χ 2=7.30,18.75, 20.89,35.54,22.43,16.05,21.31,13.97,10.33,23.96,16.25,17.74, P <0.05). Multivariate Logistic regression analysis showed that female, non breastfeeding, separation from parents, long term school meals, low consumption of staple food/staple food dominated by rice, and never eating vegetables were positively correlated with FC( OR =1.37,1.96,1.52,2.07,1.76,1.58,2.31, P < 0.05 ). Conclusions The prevalence of functional constipation is higher in primary and middle school students. Attention should be paid to factors related to students dietary habits and food classification to prevent the occurrence of FC in primary and middle school students.