Studying the coordinated development level and influencing factors of the Ecology-Economy-Society coupling system in national park regions holds significant academic value and practical importance for promoting the synergistic advancement of national park conservation and regional sustainable development. This research takes the regions encompassing 46 terrestrial and land-sea integrated national parks (including candidate areas) in China as the study areas. The authors construct an evaluation index system for assessing the coordinated development of the Ecology-Economy-Society system, employs the entropy weight method to determine indicator weights, and utilizes coupling coordination degree and obstacle degree models to analyze the temporal and spatial evolution characteristics of the coupling coordination and the primary constraining factors within these regions from 2015 to 2023. It is found through this study that: (1) The ecological, economic, and social indices of the national park regions increased significantly from 2015 to 2023, with the mean comprehensive index rising from a relatively low to a relatively high level, which indicates comprehensive progress in ecological integrity, economic vitality, and social well-being. The economic subsystem exhibited the most pronounced evolution, yet regional disparities continued to widen; (2) The coupling coordination degree in national park regions improved markedly during the study period, transitioning overall from a low-level equilibrium stage (mean 0.124) to a synergistic development stage (mean 0.461). The interaction within the Ecology-Economy-Society system entered a virtuous cycle, with the institutional guarantee advantages of established national parks demonstrating clear positive benefits, and the pilot policies in candidate areas showing relatively significant effectiveness; (3) The evolution of the Ecology-Economy-Society system in national park regions exhibited phased differentiation characteristics. Established parks formed mature development models leveraging their institutional advantages; parks in the application phase achieved only marginal improvements constrained by policy stages; and candidate parks experienced slow progress in coordinated development due to a lack of institutional supply. Spatial imbalances in natural endowment and resource allocation constituted barriers to ecological value transformation and synergistic development; (4) National park establishment fosters regional synergy through institutional restructuring and capital allocation. The governance system promotes the circular flow of ecological and social capital by integrating management functions, establishing coordination mechanisms, and guiding resource investment. Ecological resources realize market value through multi-level transformation chains, driving the ecological transition of local industries. This study deepens the understanding of the multidimensional functional relationships between national park development and regional sustainable development in China. By revealing the synergistic mechanisms and obstacle factors among the ecological, economic, and social subsystems within these regions, it provides a scientific support for advancing the institutional construction of China's national park system as well as formulating refined and categorized policies.