Abstract: Objective To explore the association between the number of fast-food restaurants around schools and obesity among primary students,and to provide a scientific evidence for the making preventive measures of childhood obesity.Methods Cluster random sampling method was employed to select 822 students from grade 3-5 in 10 primary schools in one urban district of Beijing.And their body weight and height were measured.The fast-food restaurants within an 800 m buffer of school centroids were searched through Baidu Map.Other information associated with obesity,such as age,gender,dietary behaviors,physical activity,screen-based sedentary behaviors of students and body weight,height,education of parents,were obtained through questionnaires.A two-level logistic regression model was used to examine the association between fast-food restaurants around schools and obesity among primary students while controlling for other individual and family factors.Results The average number of fast-food restaurants around the 10 schools was(4.20-±2.74).The prevalence of obesity was 8.64% among primary students,12.50% among boys and 4.83% among girls.The differences were of statistical significance(x2 =15.315,P<0.01).Without controlling for other individual and family factors,the number of the fast-food restaurants around schools was a risk factor for childhood obesity with the OR of 1.092(95%CI:1.001-1.190).After controlling for these factors,the association still existed with the OR of 1.138(95%CI:1.030-1.258).Conclusion The number of the fast-food restaurants around schools was a risk factor for childhood obesity and had an independent influence onobesity among primary students.