Leisure-time physical activity has changed over the past few decades. Participation in diverse sports programs by children and adolescents is more conducive to increasing physical activity levels and promoting individual health. The purpose of this study was to explore the correlation between adherence to participation in diversity of sports programs and physical fitness among children and adolescents, in addition to analyzing individual attitudinal, family, and school dimensional factors that influence children's and adolescents' participation in diversity of sports programs. This study included cross-sectional data from 3309 child adolescents. Next, physical fitness indicators were also included. The study used Pearson correlation analysis, one-way ANOVA, and linear regression. Pearson correlation and one-way ANOVA were used to explore the correlation between diversity and physical fitness in participating sports and the differences in physical fitness between different sports groups. In addition, the linear regression method was used to analyze the impact of diversity on physical fitness. Finally, ordinal logistic regression was used to analyze the influencing factors of diversity in participating sports programs.Significant correlations were observed between diversity of participation in sports programs and various physical fitness indicators across all age groups, including muscular strength, speed, endurance, and flexibility (p < 0.01). Additionally, physical fitness levels significantly differed among groups with different numbers of sports participation (p < 0.05).Furthermore, misconceptions about physical activity were identified as a negative factor influencing sports program diversity (β = -0.193, p < 0.01), whereas willingness to consistently engage in physical activity was a strong positive predictor (β = 0.494, p < 0.01). Longer screen time negatively affected sports program diversity (β = -0.047, p < 0.05), and difficulty completing school physical education requirements was also a limiting factor (β = -0.112, p < 0.05). In contrast, peer influence served as a positive factor promoting sports program diversity (β = 0.071, p < 0.01).Conclusion: Greater diversity in sports program participation is associated with better physical fitness outcomes and contributes to overall health promotion in children and adolescents. Sustained participation in a variety of sports programs requires broader social support, especially from families and peers, which may enable more youth to remain engaged in diverse physical activities. Participation in diverse sports programs can bring lasting benefits and is recognized as a key element of a healthy lifestyle. Therefore, more targeted strategies are needed to increase participation in both diverse sports programs and general physical activity among youth.