Objective: To explore the cross sectional and longitudinal relationships between children s 24 h movement behaviors and health related quality of life (HRQoL), and to reflect the impact of reallocating time between different activities on HRQoL scores using the isotemporal substitution analysis method, so as to provide a scientific basis for promoting children s health. Methods: In May 2022, a method combining cluster random sampling and convenience sampling was employed to conduct baseline survey on 397 children aged 7-10 from three primary schools in Wanzhou District of Chongqing. Children s movement behaviors were monitored using accelerometers, and their HRQoL was assessed through a health related quality of life questionnaire for children.The same questionnaire was used for assessing HRQoL of children on the follow up survery after on year(May 2023). A component based multiple linear regression model was used to analyze the relationship between children s 24 h movement behaviors and HRQoL. Results: The average daily times for children s light physical activity (LPA), moderate to vigorous physical activity (MVPA), sleep (SP), and sedentary behavior (SB) were (331.5±41.7，61.9±28.6，561.7±78.4，484.9±67.3) min, respectively. The mean baseline HRQoL score was (69.5±6.6), and it was (67.6±5.1) after one year. MVPA and SP were positively correlated with HRQoL at baseline( β =0.59,0.38) and after one year ( β =0.48, 0.39), while SB was negatively correlated with HRQoL at baseline and after one year ( β =-0.25, -0.53) ( P <0.05). An isotemporal substitution analysis showed that replacing 30 minutes of LPA or SB with MVPA increased the HRQoL scores by 1.81 and 2.79 at baseline, and by 1.37 and 2.12 after one year. Additionally, replacing SB with SP increased the HRQoL scores by 0.61 at baseline and by 0.39 after one year ( P <0.05). Conclusions Children s 24 h movement behaviors, particularly physical activity (PA) and sleep, are closely related to children s HRQoL. Appropriate measures should be taken to increase children s PA and SP time and reduce SB time to improve children s HRQoL.