Abstract: Objective To analyze the factors of simple obesity in primary and middle school students in order to provide basis for intervention.Methods Using multi-stage stratified cluster sampling,students in 10 primary and middle schools were selected.The questionnaire survey was conducted among the students to collect information on diet,exercise and other living behavior and physical examination was carried out.Non-conditional Logistic regression was used to analyze factors of obesity.Results High-birth-weight(OR=1.357,P<0.05),high education level of the father(OR=2.048,P<0.05),eating fast(OR=1.747,P<0.05),enjoy meat(OR=3.451,P<0.05)and sweets(OR=1.379,P<0.05) were risk factors of obesity.Consumption of eggs(OR=0.628,P<0.05),taking soy products(OR=0.699,P<0.05),taking fresh fruits and vegetables(OR=0.346,P<0.05),nutritional supplements(OR=0.354,P<0.05),more physical exercise(OR=0.344,P<0.05)and long time exercise were protective factors of normal weight.Conclusion The high education level of father,diet,living behavior and high weight at birthare related to obesity among primary and middle school students in Xuzhou city.