The Poyang Lake Basin has experienced considerable land-use/cover change (LUCC) due to urbanization and climate change, impacting ecosystems and altering the provision of ecosystem services (ESs). Precise prediction of LUCC and accurate quantification of the impact of such changes on ESs are essential for effective ecological conservation and management. We assessed the Poyang Lake Basin ESs for 2000, 2010, and 2020. Additionally, we projected land-use maps for 2030 under unrestricted development (UD), ecological protection (EP), and urbanization expansion (UE) scenarios using a logistic CA-Markov improved model. Based on this, future ecosystem changes under different scenarios were revealed, and the response of ESs to different LUCCs were quantified. The findings indicated that the most significant change in the watershed over the past two decades was a 92.50% expansion of built-up land. Although ESs exhibited stability in space and time, local heterogeneity emerged under different scenarios. EP positively influenced carbon storage, habitat quality, and soil retention, while UD and UE negatively affected watershed ES index values. Farmland and woodland significantly influenced ES, contributing more than 86.06%. Conversions from farmland, woodland, and grassland to other land types negatively affected ES, while transformations from built-up and unutilized land to woodland and grassland had positive effects. The critical contributing indices in the watershed were primarily concentrated between farmland and woodland. These study results serve as a valuable reference for sustainable development and spatial planning of regional ecosystems. [ABSTRACT FROM AUTHOR]