Abstract: Objective To examine the change in body mass index (BMI) among school aged children and adolescents in Shanghai.Methods National Student Health and Physical Fitness Survey in China of 2000,2005,2010 and 2014 were analyzed.LMS method was used to assess changes of BMI for 7-18 years old children and adolescents.Results During the past 14 years,the difference of BMI in the 85th percentile was relatively small among younger children,slightly increasing with age and decreasing after puberty.Average growth rate was 2.1% and 1.3% among boys and girls,respectively.BMI growth rate was highest among middle to high percentile,especially among boys aged 7-11 years old and 12-15 year old,growth rate of BMI in the 95th percentile was 2.0% and 3.2%,respectively.Among 12-year-old boys,BMI in the 95th percentile increased from 23.4 kg/m2 to 26.8 kg/m2,while it was from 24.0 kg/m2 to 25.9 kg/m2 among 14-year-old girls.Compared with the WGOC standard,the 85th,95th percentile BMI curves of boys were higher than the overweight curves of WGOC,while the 85th curves of girls younger than l0-year-old higher than the overweight curves of WGOC.Overweight and obesity rate was 15.4% and 9.1%,respectively,which increased by 6.4 and 5.2 percentage points,respectively.Conclusion Significant changes are found in BMI at high percentiles among children and adolescents in Shanghai.Studies that characterize population change should examine pattern of change across the entire distribution and not just average trends or single indicators.