Objective: To understand physical activity status and its relation with cardiopulmonary endurance among Chinese children and adolescents, so as to provide reference for cardiopulmonary endurance improvement and intervention of Chinese children and adolescents. Methods: During September to November 2018, a stratified cluster sampling method was used to select 4 269 children and adolescents aged 7-18 years in six major regions of China, 20 m shuttle run test and physical activity were assessed. Results: Average duration for daily lowintensity physical activity among boys was (31.49±30.01) min, for moderate to vigorous physical activity (68.37±46.50) min. Average duration for low intensity physical activity among girls was (34.02±31.58) min, for moderate to vigorous physical activity was (63.02±44.91) min. The number of 20 m shuttle run test for boys reached ( 36.17 ±21.94) times, and the maximal oxygen uptake per minute was (44.51±5.05) mL/kg; the number of 20 m shuttle run test for girls reached (26.59±12.56) times, and the maximal oxygen uptake per minute was (41.99±5.29) mL/kg. There were statistically significant differences in the number of 20 m shuttle run test and maximal oxygen uptake across age groups in boys ( F= 589.37 , 152.79, P <0.01), as well as that in girls ( F=305.21, 1 032.46, P <0.01). The proportion of boys and girls who met moderate to vigorous physical activity standard was 49.24% and 42.92%, respectively. Linear regression analysis showed that there was a significant positive correlation between the duration of moderate to vigorous physical activity and maximal oxygen uptake ( β=0.11, P ＜ 0.01). Conclusion There is a significant correlation between moderate to vigorous physical activity with cardiorespiratory endurance among Chinese children and adolescents. Higher level of moderate to vigorous physical activity is important to help improve cardiopulmonary endurance among children and adolescents.