Objective: To analyze the effects of outdoor activities, sedentary behaviors and sleep duration on the risk of poor vision among primary and secondary school students after replacing them with each other, so as to provide a reference for precise intervention in the prevention and control of myopia among children and adolescents. Methods: From March to May 2023, a stratified cluster random sampling method was used to select 6 132 students in grades 4 to 12 in Hefei, Wuhu, Suzhou and Chizhou cities in Anhui Province. A questionnaire survey was conducted to collect the basic information, outdoor activities, sedentary behavior, and sleep duration, and a visual inspection was carried out by 5 m standard logarithmic visual acuity chart. The single activity model, segmentation model and isotemporal substitution model were used to analyze the relationship between outdoor activities, sedentary behaviors, sleep, and poor vision, and stratified analysis was performed by gender. Results: The detection rate of poor vision among the 6 132 primary and secondary school students was 76.9%, and the detection rate of poor vision was higher for girls ( 81.1 %) than for boys (72.6%), and the difference was statistically significant ( χ 2=61.37, P <0.01). The results of the single activity model and segmentation model showed that outdoor activity and sleep duration were correlated with a reduced risk of poor vision in primary and secondary school students ( OR =0.87, 0.88; 0.88, 0.91), while sedentary behavior was correlated with an increased risk of poor vision ( OR =1.05, 1.03) ( P <0.05). The results of the isotemporal substitution model showed that replacing the same amount of sedentary behavior with 1 h/d of outdoor activity was associated with 15% reduction in the risk of poor vision ( OR = 0.85), and replacing the same amount of sedentary behavior with 1 h/d of sleep was associated with a 12% reduction in the risk of poor vision ( OR =0.88) ( P <0.05). The results of the isotemporal substitution model stratified by gender showed that replacing the same amount of sedentary behavior with 1 h/d of outdoor activity and 1 h/d of sleep were associated with 22% and 8% reduction in the risk of poor vision in male students ( OR =0.78, 0.92), and replacing the same amount of sedentary behavior with 1 h/d of sleep was associated with 18% reduction in the risk of poor vision in female students ( OR =0.82) ( P <0.05). Conclusion Replacing sedentary behavior with 1 h/d of outdoor activity for boys and 1 h/d of sleep for girls and boys could reduce the risk of poor vision.