Objective:To analyze the trends of overweight and obesity prevalence in Chinese children, aged from 6 to 15 years old among 4 provinces and cities from 2009 to 2019.Methods:Reviewed the national multi-center epidemiological survey data of children from the National Key Technology R&D Program of China during the Eleventh Five-Year Plan (2009 to 2010) and the National Key Research and Development Program of China during the Thirteenth Five-Year Plan (2017 to 2019). The participants′ data were selected from four provinces,municipalities and autonomous region,including Beijing, Tianjin (Northern region), Zhejiang (Eastern region), and Guangxi (Southern region). Totally 14 597 pairs of 6-15 year-old children were surveyed. According to the body mass index (BMI) and standard deviation score (SDS) of children among different genders, ages, and regions, t test or chi-square test was used to evaluate the changes in overweight and obesity over a 10-year span. Results:Totally 7 721 pairs of boys and 6 876 pairs of girls were collectted in this study, whose mean age was (10.7±2.5) years. In the past 10 years, the overall BMISDS were 0.39±1.24 and 0.36±1.31 and the overall obesity rate were 11.8% ( n=1 773) anel 12.5% ( n=1 813) of children in the 4 administrative regions did not have statistically significant differences (all P>0.05). However, the overall overweight rate rose from 17.1% ( n=2 496) to 19.1% ( n=2 781) (χ2=18.657, P<0.01), and the average annual growth rate was 0.20%. The BMISDS in the Eastern region increased from 0.10±1.07 to 0.19±1.22 ( t=-4.095, P<0.01), and the overweight rate and obesity rate increased by 3.8% ( n=202) and 3.1% ( n=169) respectively (both P<0.01); the BMISDS in the Northern region and the obesity rate did not have statistically significant differences(all P>0.05), but the overweight rate rose from 20.5% ( n=1 233) to 22.8% ( n=1 365) significantly (χ2=7.431, P<0.01); BMISDS in the Southern region was significantly decreased from 0.30±1.19 to 0.09±1.25 ( t=1.426, P<0.01), and the rate of obesity decreased from 9.8% ( n=315) to7.9% ( n=256) (χ2=6.46, P<0.05), the overweight rate was not stafistically significant ( P=0.10), respectively. The obesity rate of boys had risen from 16.4% ( n=1 265) to 18.2% (1 407) (χ2=8.997, P<0.01) in the past 10 years, and the overweight rate had risen from 18.0% ( n=1 393) to 20.5% ( n=1 579) (χ2=14.26, P<0.01). The overweight+obesity rate rose from 34.4% ( n=2 658) to 38.7% ( n=2 986) (χ2=29.859, P<0.01), and the weight problem in the age group of 8 to 11 years was particularly severe (all P<0.01). The obesity rate of girls dropped from 6.8% ( n=468) to 5.9% ( n=406) (χ2=4.546, P<0.05), the overweight rate rose from 16.0% ( n=1 103) to 17.5% ( n=1 202) (χ2=5.006, P<0.05), and the overall overweight+obesity rate rose from 22.8% ( n=1 571) to 23.4% ( n=1 608) (χ2=0.53, P>0.05). Conclusions:The growth rate of obesity among children in China had slowed down from 2009 to 2019, but the overweight rate was still on the rise. The overall base of overweight and obesity population continued to expand. The weight problem of peri-adolescent boys was particularly prominent. The current status of obesity epidemics in different regions, ages, and genders are significantly different and had their own characteristics. It is necessary to establish a personalized prevention and control strategy.