【Objective】 To analyze the incidence of overweight and obesity of 10~17 years old teenagers in Shanghai in 2011 and identify the influencing factors. 【Methods】 With the samples of 7 737 youth physical assessment data in Shanghai horizontal research part of the Metabolic Syndrome Project supported by national The Eleventh Five Year Plan,adopt China (WGOC) and the International Obesity Task Force (IOTF) childhood BMI standard used to calculated the incidence of overweight and obesity,compared the difference of this two standard,and analyzed the influencing factors of childhood overweight and obesity. 【Results】 Among 7 737 teenagers of 10~17 years old investigated,the incidence of overweight and obesity was 11.9%,6.2%(WGOC); and 13.6%,3.6%(IOTF).Boys' incidence of overweight and obesity was 17.5%,7.7%;being 6.0%,and 4.6% in girls.The results of Chi-square test suggested that gentle,age,birth weight,family revenue,father childbearing age and mother childbearing age,father's degree,father smoking,mother smoking,mother drinking,father overweight,mother overweight,patriarchal history of hypertension,diabetes,hyperlipaemia,coronary disease,fatty liver and matrilineal history of fatty liver were associated with teenagers' overweight and obesity.The results of Logistic regression analysis suggested that gentle(P＜0.001,OR＝3.376),age(P＜0.001,OR＝1.736),family revenue(P＝0.001,OR＝1.467),mother childbearing age(P＝0.023,OR＝0.704),father overweight(P＜0.001,OR＝1.545),mother overweight(P＜0.001,OR＝3.14),patriarchal history of hyperlipaemia(P＝0.018,OR＝1.293)were associated with overweight and obesity of teenagers. 【Conclusions】 Nearly 20% of the teenagers in Shanghai has overweight and obesity,being a high level in China.The major risk factors for teenagers' overweight and obesity are gender,age,family history,etc.