Abstract: As a key resource-based city in the Inner Mongolia Autonomous Region of China and an important component of the northern ecological security barrier, Ordos’s pursuit of high-quality and sustainable development largely depends on the harmonious interaction between its natural resource endowment and its socio-economic system. However, current research in this field still exhibits some limitations: (1) Studies often focus on single or dual elements among water resources, water environment, and water ecology, with insufficient attention to their synergistic evolution, nonlinear feedback mechanisms, and combined effects. There is a notable lack of dynamic coupling analysis of the "natural-socioeconomic" complex system. (2) Limited attention has been given to northern regions with constrained resource endowments and substantial spatial heterogeneity. Moreover, existing coupling coordination models do not adequately integrate the resource characteristics and spatial variability of these areas, making it difficult to accurately capture the spatiotemporal evolution patterns of regional resource systems. (3) Regarding the prediction of coupling coordination degree, most previous studies have primarily focused on developing predictive models to reveal temporal trends or simulating future scenarios, with limited investigation of the driving effects of specific indicators. This has impeded a systematic understanding of the differential impact mechanisms of various indicators on future coordination development. Therefore, this study investigates the coordination between Water-Resources, Water-Environment, and Water-Ecology (collectively termed the "Three-Water" system) and its socio-economic system in Ordos from 2000 to 2023, focusing on Ordos city and its administered banners/districts. A comprehensive evaluation index system was developed, integrating the Analytic Hierarchy Process (AHP) with the entropy weight method. This combined approach effectively merges subjective expert judgment with objective data patterns to determine indicator weights. The coupling coordination degree model (CCDM) was employed to quantify the interaction and coordination level between the two systems across time and space. Furthermore, grey relational analysis (GRA) was applied to identify the underlying driving mechanisms governing this relationship. To project future trajectories, the Grey Prediction Model GM (1,1) was used to forecast the evolving trend of coupling coordination over the next decade (extending to 2035). The key findings are summarized as follows: (1) Overall Development Trend: The mean comprehensive evaluation indices for both the "Three-Water" system and the socio-economic system in Ordos exhibited a fluctuating yet overall upward trend during the study period, indicating general progress in systemic development. However, the systems consistently displayed an "economy-lagged" pattern, suggesting that economic growth has not fully kept pace with the supportive capacity and constraints of the "Three-Water" system, revealing a structural imbalance. (2) Spatial Coordination Analysis: The coupling coordination degrees across most banners/districts primarily fell within the categories of dysfunctional recession or transitional types. This indicates that suboptimal coordination between the systems was widespread in the region, and this general pattern persisted throughout the observed period. (3) Regional Disparity and Evolution: Significant disparities in coordinated development levels among different banners/districts were not strongly pronounced. More importantly, the overall trajectory of the systems is positive, demonstrating a gradual shift from lower-level coordination towards more advanced and harmonious development types, indicating a promising transitional phase. (4) Identification of Key Drivers: Analysis of the driving factors revealed the following ranking of overall influence intensity: Socio-economic factors > Water-Ecological factors > Water-Resource factors > Water-Environmental factors. This hierarchy emphasizes the dominant role currently exerted by socio-economic development pressures and policy interventions relative to other components of the "Three-Water" system. The forecast generated by the GM (1,1) model presents an optimistic outlook: between 2025 and 2035, the coupling coordination degree of the systems in the study area is expected to achieve a substantial improvement, potentially advancing from intermediate levels to stages of intermediate and even good coordination. Further analysis identified specific factors that will be critical in driving this enhanced coupling coordination: GDP per capita (reflecting economic development level), ecological and environmental water replenishment (representing ecological restoration efforts), water resource development and utilization rate (indicating resource use efficiency), and water consumption per 10,000 yuan of industrial value-added (reflecting the application of water-saving technologies). These factors are recognized as the primary drivers guiding the two systems towards a more synergistic and sustainable future. This research provides a scientific foundation and decision-making support for Ordos and similar resource-based regions to achieve a balanced development pathway that aligns economic growth with water resource conservation, environmental protection, and ecological sustainability.