The Impact of Urban–Rural Integration Policies on Regional Sustainable Development

Against the backdrop of coordinated advancement in new urbanization and rural revitalization strategies, the integration of urban and rural areas serves as a core approach to dismantling the urban–rural dichotomy and driving high-quality regional development. The enabling effects of its policy implementation on regional sustainable development have garnered significant attention. As pivotal conduits where urban and rural elements converge, peri-urban fringe zones have emerged as the primary arena for policy implementation and impact realization. Using panel data from 268 prefecture-level and above cities in China from 2015 to 2024 as the sample, this study treats the establishment of urban–rural integration pilot zones as a quasi-natural experiment. Employing a multi-period Difference-in-Differences model, instrumental variables method, and spatial econometric model, it systematically investigates the impact effects, operational mechanisms, heterogeneous characteristics, and spatial spillover effects of urban–rural integration policies on regional sustainable development. Findings reveal that urban–rural integration policies significantly promote regional sustainable development. This conclusion remains robust after endogeneity treatment and stability tests, with policies demonstrating stronger enabling effects on ecological sustainability than on economic and social sustainability, forming a development pattern characterized by “ecological priority and multidimensional coordination”. Policies achieve synergistic enhancement of regional economic, ecological, and social sustainability through three pathways: optimizing urban–rural factor allocation, establishing ecological co-governance systems, and advancing equitable public services. Policy effects exhibit significant heterogeneity: the stronger the urban baseline conditions, the more pronounced the policy’s enabling effect, while excessive population concentration exerts a marginal negative impact on ecological sustainability. Urban–rural integration policies generate a significant positive spatial spillover effect, accounting for 38.9% of the total effect. This spillover gradually diminishes with increasing distance within a 120 km radius, with geographic distance and administrative barriers serving as core constraints. This study provides empirical insights and practical pathways for optimizing urban–rural integration policy design and advancing regional sustainable development.