Objective To conduct a scoping review to explore the application of Just-in-time adaptive intervention (JITAI) in physical activity promotion, and to provide reference for future research and clinical application.Methods Based on the scoping review framework proposed by Arksey and O′Malley, relevant literature regarding JITAI in physical activity promotion was searched in English-language and Chinese-language bibliographic databases from inception of each database to June 20, 2024.The included literature was summarized and analyzed.Results A total of 22 publications were included.JITAI was mainly conducted via smartphone and Apps.JITAI targeted students, occupational populations, older adults, overweight/obese people and patients with chronic di-seases.Theories for guiding the construction of JITAI were the Theory of Behavior Change and the Fogg Behavior Model.The intervention design framework included long-term outcome, short-term outcome, decision points, intervention options, tailoring variables and decision rules.The outcome indicators included eight aspects:sedentary time, activity level, walking distance, psychological/emotional state, quality of life, physiological parameters, feasibility and acceptability.Conclusion JITAI has the advantages of ecological validity, adapted and system-triggered support, and fun in increasing physical activity.In the future, it is necessary to conduct large-sample, high-quality randomized controlled studies, pay attention to the characteristics and needs of the representative populations, improve protocol design, optimize decision rules, consider the feasibility and acceptability of intervention delivery, thus to enhance the impact of JITAI in physical activity promotion.