<p>Sustainable water resource management requires a research framework that integrates river hydrological health with multi-objective reservoir operations, where ecological flow is a key determinant of river hydrological health. In this study, we focused on the Haokun-Chengbi River cascade reservoirs throughout different years. A multi-objective optimization model was developed to maximize power generation and water supply while minimizing ecological overflow and water shortage. The model was developed using the NSGA-III algorithm, which is suitable for complex nonlinear conflict problems. In this study, we introduced the river hydrological health level and analysed the impact of reservoir operation on river hydrological health by comparing the river hydrological health status before and after reservoir operation. A framework for multi-objective reservoir optimization and river hydrological health assessment was established. The results show that as inflows decrease, cascade reservoir power generation, water supply, and ecological overflow and water shortage decrease. The different outcomes across typical years emphasize the necessity of adaptive reservoir operation strategies under varying hydrological conditions. Further analysis of the three objectives showed that the conflict between hydropower generation, ecological overflow and water shortage is the most pronounced. As a measurement indicator, the hydrological health level is strongly affected by natural water after optimized scheduling, which conflicts with the water supply target. Notably, the improvement in river hydrological health is most pronounced in dry years, reaching as high as 57.35%. This study is a useful reference for sustainable development in reservoir operation and management under different water inflow scenarios.</p>