Integrating Structural Supply and Supply–Demand Matching to Assess Urban Ecological Recreation Spaces Equity: A Case Study of Urumqi City

Urban ecological recreation space (UERS), as a crucial component of urban blue–green infrastructure, plays a pivotal role in supporting daily recreational activities and enhancing urban ecological resilience. However, existing equity studies often focus on supply–demand matching outcomes while neglecting the structural allocation of green space provision. Against this backdrop, this study constructs a dual-layer analytical framework of “structural supply–supply–demand matching” and introduces a quality factor to improve the Gaussian two-step floating catchment area method (G2SFCA). Focusing on Urumqi as an empirical case, the accessibility and equity of its UERS are analyzed. The results indicate: 1. The accessibility of UERS exhibits a “core–periphery” differentiation, with the old urban area demonstrating higher accessibility levels in terms of structural supply. However, due to the competitive effects of high population density, its accessibility advantage in the supply–demand matching layer is significantly diminished. 2. Population competition amplifies spatial imbalances, resulting in significantly higher inequality at the supply–demand matching layer than at the structural supply layer. 3. After considering the quality factors of UERS, its fairness has improved, which is more pronounced in the supply–demand matching layer. Optimizing the quality of UERS in high-density built-up areas contributes to the enhancement of fairness. This study emphasizes that UERS accessibility should be understood as a coupled outcome of structural supply and competitive redistribution. The proposed dual-layer framework provides a more comprehensive basis for diagnosing spatial inequalities and formulating differentiated blue–green infrastructure planning strategies.