<p>Exploring the interrelations and synergistic effects among digital technology (DT), new-type urbanization (NU), and urban ecological resilience (UER) within a systematic framework is crucial for high-quality urban development. This study constructs and analyzes a composite system (DNU) composing DT, NU, and UER subsystems. Based on panel data from the Yangtze River Delta Urban Agglomeration (YRDUA) spanning 2011–2022, the Critic-Entropy method is employed to assess the development status of the subsystems, while PVAR and Tapio models are used to identify their dynamic relationships. The coupling coordination degree (CCD), modified gravity, and obstacle degree (OD) models are integrated to quantify the DNU system's coupling effects and related characteristics. The principal conclusions are: (1) DT in YRDUA lagged NU and UER but had a higher growth rate. DT and NU exhibited significant spatial differentiation, while UER was relatively balanced. (2) DT, NU, and UER were all self-enhancing. DT positively influenced NU and UER, but both NU and UER currently constrained DT. NU and UER showed a good dynamic adaptation relationship, but DT's adaptation to both needs improvement. (3) The CCD of the DNU system steadily increased to an intermediate coordination state, with the NU-UER binary system contributing the most. Spatially, the CCD exhibited a metropolitan area clustering pattern and a "center-periphery" network structure. Social and economic urbanization and ecological restorative capacity were identified as the main obstacles to CCD.</p>