Objective: To understand the malnutrition status and trends among children and adolescents, and to provide evidence for improving the nutritional status of children and adolescents in 9 provinces of China. Methods: A total of 5 746 children and adolescents aged 7-17 years old from the "China Health and Nutrition Survey" in 2000, 2006, 2011, 2015 and 2018 were selected as the subjects. Variance analysis and Chi square test were used to analyze the BMI of children and adolescents with different characteristics and different types of malnutrition. Linear regression model was used to analyze the trends of BMI, stunting and wasting, and overweight and obesity in children and adolescents with different characteristics. Results: From 2000 to 2018, the BMI of children and adolescents aged 7-17 increased from 17.66 kg/m 2 to 19.08 kg/m 2 ( F =22.88, P <0.05). The prevalence of overweight and obesity increased in both males and females( t =16.65,11.01, P <0.05). Comparison of the rates of wasting and Growth Retardation and overweight and obesity among children and adolescents aged 7-17 years in nine provinces in 2000, 2006,2 011, 2015 and 2018, the difference was statistically significant ( χ 2 wasting and grouth retardation =85.46, 29.55, 41.09, 29.86, 45.29; χ 2 overweight and obesity = 109.12 , 52.21, 98.23, 68.27, 52.49, P <0.05). Conclusion The prevalence of stunting and wasting of children and adolescents aged 7-17 in 9 provinces of China decreased. The prevalence of overweight and obesity showed an upward trend in 9 provinces of China. There were regional differences among the prevalence of stunting and wasting, as well as overweight and obesity. Active intervention strategies and measures should be taken to improve malnutrition and focus on the prevention of obesity in children and adolescents in China.