Abstract: Through literature review and field research, this study interprets the essence of informal sports organizations and elucidates the logic behind their emergence within the context of advancing the national fitness strategy. Furthermore, practical pathways are proposed to address current challenges. The study posits that the core of informal sports organizations lies in meeting diverse demands for sports activities, characterized by goal randomness, high-level flatness, strong agency attributes, rapid and extensive generativity, dual-value facets, and dependence on digital technology. In theory, the generation of informal sports organizations is a complex process involving multiple factors and layers, encompassing individual needs, social relationships, and identity recognition.From historical to present contexts, informal sports organizations align with the requirements of national fitness development and play a crucial role in innovating national fitness participation concepts, improving resource allocation efficiency, and compensating for the shortcomings of formal sports organizations. However, during the implementation of the national fitness strategy, informal sports organizations face challenges such as limited integration channels, weak endogeneity, and institutional conflicts. To enhance the depth, sustainability, and effectiveness of informal sports organizations, it is recommended to address these challenges through practical measures such as channel unblocking, cultivating endogenous motivation, and promoting institutional compatibility.