[Objective] To explore the interactive coordination effect between urban green land use efficiency and high-quality urban development，and to provide scientific insights for facilitating the green transition in urban land utilization and advancing regional high-quality development. [Methods] Taking 41 prefecture-level cities in the Yangtze River Delta region as research subjects，this study constructed an evaluation index system. Then，urban green land use efficiency and high-quality development index during 2008—2022 were assessed，employing the Super-EBM with undesirable outputs and the entropy-TOPSIS model， respectively. A panel vector autoregression （PVAR） model was also adopted to reveal their interactive relationships. Furthermore， an improved coupling coordination model and GM（1，1）gray prediction model were applied to investigate their spatiotemporal coordination characteristics and future evolution trends. [Results] 1）The urban green land use efficiency in the Yangtze River Delta region demonstrated a fluctuating upward trend，exhibiting spatial patterns characterized by ″westward retreat with eastward advancement and progressive homogenization ″. Meanwhile， high-quality development displayed pronounced non-linear growth trends，forming a prominent spatial pattern marked by ″core-periphery radiation with axial extension ″. 2）The analysis revealed a bidirectional causal relationship between urban green land use efficiency and high-quality development index. Both of them experienced bidirectional shocks（endogenous and cross-systemic），but were driven predominantly by endogenous structural factors，thus demonstrating inertial dependence characteristics. High-quality development exerted a stronger promoting effect on urban green land use efficiency. 3）The coupling coordination between the two systems showed consistent growth，exhibiting a clear regional hierarchy：Shanghai > Jiangsu > Zhejiang > Anhui. Spatially，it manifested characteristics as follows：southern regions outperformed their northern counterparts， coastal areas demonstrated superior coordination to inland zones， while central cities exhibited significant developmental uplift. A ″Z-shaped ″axis pattern centered on developed cities emerged clearly. The coordination was expected to continuously improve， but the core-periphery distribution situation would be consolidated. [Conclusion] By fully implementing the requirements of high-quality development，leveraging the spillover effect of core growth，and implementing targeted policies for different types of cities，overall interactive and coordinated regional development can be achieved.