The scientific evaluation of the coordinated development level of the Yangtze River Delta Urban Agglomeration is crucial for promoting the localization of the Sustainable Development Goals (SDGs). This study, based on the SDGs framework, utilizes data from 41 prefecture-level cities in the Yangtze River Delta from 2013 to 2023 to establish a five-dimensional evaluation index system, covering urban–rural integration (SDG 10), scientific and technological innovation (SDG 9), infrastructure (SDG 9.1), ecological environment (SDG 13/14/15), and public services (SDG 3/4/11). By applying the coupling coordination degree model, kernel density estimation, and the standard deviation ellipse method, the study systematically assesses the regional coordinated development level and its spatio-temporal evolution patterns. The findings reveal that from 2013 to 2023, the development indices of the five subsystems showed a fluctuating upward trend, with significant disparities in growth rate and stability. The overall regional coordination degree continuously improved, and differences diminished, with the coupling degree and coupling coordination degree exhibiting a “polarization followed by an overall leap” pattern. The coupling coordination degree evolved in three stages: “imbalance in mutual feedback among elements, strengthening of coordination mechanisms, and deepening of policy innovation”, with spatial differentiation and clustered development coexisting. Spatially, the distribution center shifted through three phases: “policy-driven”, “market-regulated”, and “technology-led”, forming an axial reconstruction from northwest to southeast, ultimately establishing a multi-center coordinated development system.

Amid the deep integration of China’s “dual-carbon” goals with regional coordinated development strategies, this study develops a multidimensional analytical framework of regional integration based on panel data from 41 prefecture-level cities in the Yangtze River Delta urban agglomeration from 2009 to 2023. The framework encompasses five dimensions: urban–rural integration, innovation coordination, infrastructure connectivity, ecological co-governance, and public service sharing. Using structural equation modeling (SEM), the study empirically investigates the mechanisms and pathways through which regional integration shapes low-carbon development. The results indicate that different dimensions exert differentiated impacts: urban–rural integration and infrastructure connectivity significantly promote low-carbon development, whereas public service sharing has an adverse effect due to a phenomenon known as “carbon lock-in”. By contrast, the impact of innovation coordination and ecological co-governance is not statistically significant. Moreover, substantial regional heterogeneity exists: Jiangsu Province demonstrates the leading performance in the manifest development level; Zhejiang Province shows strong systemic capacity level, but limited conversion into manifest outcomes. At the same time, most cities in Anhui Province lag in both aspects. Coordination analysis further identifies four typical development patterns: dual-high, system-driven, performance-dominant, and dual-low. Drawing on these findings, this study proposes policy recommendations across four dimensions—regional coordination, low-carbon pathway optimization, targeted empowerment, and collaborative governance—to facilitate the green and low-carbon transition of the Yangtze River Delta urban agglomeration.