Objective To observe the prevalence of overweight and obesity among school-age children in Yan 'an and to analyze risk factors for preventing from overweight and obesity. Methods Three primary schools located in urban and suburban district were respectively selected by a cluster sampling method.Morphological indicators including height,weight and body mass index (BMI) were collected,and questionnaire survey on children's character,exercise,sleep,diet was conducted. Results 1)The prevalence of overweight was 13.76%,of which the urban boy 20.09%,urban girl 10.64%,suburban boy 14.83%,suburban girl 8.19%; the prevalence of obesity was 5.27%,of which the urban boy 8.04%,urban girl 4.47%,suburban boy 4.78%,suburban girl 3.00%.2)The factors involving gender,residence distribution,character had significant influences on the students' overweight and obesity(P<0.05). Conclusions The current status of Yan 'an children's overweight and obesity is higher.Basic prevention from overweight and obesity should be reasonable diet and physical exercise