[Objective] A nature-based solutions （NbS） synergistic benefit assessment framework applicable to the Dongting Lake ecological economic zone was constructed，in order to seek differentiated NbS implementation schemes to enhance regional hydrological rhythm adaptation index，and to provide operable optimization pathways for the hydrological dynamic management in ecologically sensitive areas. [Methods] Taking the Dongting Lake ecological economic zone as the study area， this study constructed an NbS synergistic benefit assessment framework integrating the hydrological rhythm adaptation index （HRAI） and the InVEST model， comprehensively analyzing the effects of NbS on flood regulation， ecological water supplementation， and flow stability. [Results] ① The regional annual average HRAI increased from 0.317 in 2022 to 0.327 in 2024， indicating that NbS measures effectively improved flood regulation and eco-hydrological stability. ② Hilly wetlands and forests could synergistically enhance rhythm adaptation index and the supply capacity of ecosystem services such as water yield and soil conservation， while improvements in lakeside plains and built-up areas were limited. [Conclusion] It is recommended to prioritize the implementation of ecological ditches and vegetation restoration projects in hilly wetlands， promote the construction of ecological slow-release and time-based regulation systems in plain areas， and promote sponge measures such as rain gardens and permeable pavements in built-up areas. This will increase available water content， extend ecological water supplementation days， and optimize flood pulse thresholds， thereby achieving a steady improvement in the HRAI.