Objective To summarize the best evidence of early mobilization of critically ill children, and to provide references for clinical staff to formulate related intervention strategies. Methods Relevant literature on early activity in critically ill children was retrieved from databases such as the Registered Nurses′ Association of Ontario (RNAO), the National Institute for Health and Care Excellence (NICE), the Scottish Intercollegiate Guidelines Network (SIGN), Web of Science, Cochrane Library, PubMed, Best Practice (BMJ), UpToDate, SinoMed, Wanfang Data, and China National Knowledge Infrastructure (CNKI), up until August 14, 2023. Quality assessment was conducted according to JBI criteria, with evidence extraction being performed on the included publications. Results A total of 10 publications were eligible, and 20 pieces of best evidence were extracted and factored into 6 dimensions：team, assessment, absolute contraindications, relative contrain dications, exercise monitoring and activity contents. Conclusion The best evidence on early mobilization of critically ill children serves as an evidence-based basis for clinical staff to implement early mobilization and rehabilitation for critically ill children.