Objective: To systematically review the efficacy of organized physical activity intervention from 1992 to 2020 on physical fitness of young children aged 3-6 in China. Methods: Studies were searched in databases of CNKI, Wan Fang, VIP, EBSCO Sports and Web of Science. The randomized controlled trials of physical fitness of young children aged 3-6 in China were selected by using Chinese and English keywords: (preschool OR kindergarten OR young children OR nursery) AND (physical fitness) AND (randomized controlled trial) AND (Chinese OR China). Results: Twenty three studies were included, involving 2 386 young children. Meta analysis showed that physical activity had a moderate to high effect on young children s standing long jump ( SMD =0.61, 95% CI =0.46-0.76), sit and reach ( SMD =0.53, 95% CI =0.36-0.70), 10 meter shuttle run ( SMD =-0.84, 95% CI =-1.08- -0.61), continuous jumping on two feet ( SMD =-0.74, 95% CI =-0.90- -0.58), and walking the balance beam ( SMD =-0.54, 95% CI = -0.70- -0.39). On the other hand, physical activity had a small effect on young children s throwing ball ( SMD =0.39, 95% CI =0.26-0.51). Conclusion Physical activity intervention shows significant effects on physical fitness of young children in China. Effecs on physical fitness indicated by different types of indicators depends on physical activity content, duration, frequency, child age and other factors.