Objective: To explore age, gender, and regional differences in physical activity among children and adolescents in China, and to provide a scientific reference for enhancing physical activity promotion. Methods: A total of 4 269 children and adolescents aged 7 to 18 years were selected from six administrative regions of China (East China, Northwest China, North China, Central China, Southwest China and South China) using a stratified random cluster sampling method from September to December 2018. A questionnaire was administered to evaluate the physical activity level of Chinese children and adolescents aged 7 to 18. Results: The overall detection rate of MVPA insufficiency in children and adolescents in China was 53.8%, of which the detection rate of MVPA insufficiency was 50.8% among boys and 57.1% among girls. Gender differences were statistically significant ( χ 2= 17.10 , P <0.05). Among the different age groups, the lowest detection rate of MVPA among 10-12 year olds was 43.6%, whereas the highest rate among 16-18 year olds was 63.0%, with significant differences between gender ( χ 2=4.33, 30.79, P <0.05). The P 50 values of total physical activity(TPA), light intensity physical activity(LPA), moderate intensity physical activity(MPA), vigorous intensity physical activity(VPA), moderate to vigorous physical activity(MVPA) were 92.9,24.3,41.4,7.1 and 55.7 min/d , respectively. The P 50 values of physical exercise, housework activities, entertainment activities and transportation activities were 34.3 , 2.1, 2.3 and 30.0 min/d, respectively, and the difference in age groups was statistically significant( H =95.03, 74.99, 300.26 , 64.16, P <0.05). There was a statistically significant difference in the detection rate of insufficient MVPA among children and adolescents in different regions ( χ 2=83.91, P <0.05). The lowest rate was 44.0% in North China, and the highest was 65.9% in East China. Conclusion The detection rate of MVPA insufficiency among Chinese children and adolescents firstly decreased and then increased with age. Boys participated in higher levels of physical activity than girls.