Urban-rural imbalance impedes sustainable development in modernizing nations. This paper examines China’s urban-rural relations via symbiosis theory, building a model and index system to assess urban-rural symbiosis, contributing to SDG 11 (Sustainable Cities and Communities) and SDG 10 (Reduced Inequalities). Focusing on 31 provinces and cities in China, this study uses data from 2022 and the entropy weight method to evaluate the current urban-rural symbiosis relationship in China. Findings highlight unsustainable urban-rural relations: Firstly, imbalances persist between urban and rural areas in China regarding resource allocation, public services, and development speed, hindering sustainable and equitable development. Secondly, spatial differentiation and insufficient flow of factors significantly restrict the development of urban-rural symbiosis, impacting resource efficiency and balanced regional growth. Thirdly, the levels of cultural and ecological symbiosis between urban and rural areas are low and uneven, posing risks to environmental sustainability and social cohesion. Recommendations include strengthening rural units for collaboration, using counties to improve the symbiosis interface, and optimizing the symbiotic environment. These measures aim to guide, incentivize, coordinate, and protect positive urban-rural relations, driving symbiosis towards a more balanced, inclusive, sustainable urban-rural development model for China, offering insights for similar nations.

Against the backdrop of the concurrent advancement of rapid urbanization and large-scale urban renewal, enhancing urban livability has become an important issue in China’s urban development. This study employs a Genetic Algorithm-optimized Projection Pursuit (GAPP) model to assess livability in 125 Chinese cities (2010–2022). Integrating spatial analysis and Geographically Weighted Regression (GWR), we investigate livability’s spatiotemporal evolution and the spatially heterogeneous impacts of urban renewal. Empirical findings reveal three major characteristics. First, urban livability exhibits robust spatial “disequilibrium and lock-in,” with coastal regions forming high-value clusters, while the Northwest and Northeast remain entrenched in cold spots. Second, regional divergence continues to widen, accompanied by a profound structural mismatch characterized by “macro-level convergence versus micro-level polarization.” Third, while urban renewal catalyzes livability improvement, its efficacy follows the law of diminishing marginal returns. Marginal improvements are pronounced in the baseline-depressed Northeast but severely diminish along the infrastructure-saturated southeastern seaboard. These findings validate the spatial non-stationarity of human habitat evolution. We argue that policymakers should abandon “spatially blind” physical expansion paradigms and instead promote context-specific organic renewal and asymmetric resource allocation to bridge regional livability divides.