Abstract: Carex tussock wetlands, as a unique herbaceous swamp ecosystem, play a crucial ecological role in maintaining wetland ecosystem stability, biodiversity, and carbon sequestration. However, in recent years, the degradation of Carex tussock wetlands has become increasingly evident, but research on their natural degradation process under hydrological stress remains limited. This study focuses on the degradation of Carex tussock wetlands and their response patterns to hydrological conditions, using the Momoge National Nature Reserve (Jilin Province, China) as the research site. By comparing the soil physicochemical properties and morphological characteristics of degraded and non-degraded tussocks, and simulating hydrological conditions using the Mike21 hydrodynamic model, the key hydrological factors influencing the degradation of Carex tussock wetlands and their ecological response mechanisms were explored. The results showed that the severely degraded tussock areas had the lowest elevation ((135.93 ± 0.03) m), while the lightly degraded tussock areas ((136.21 ± 0.06) m) had a slightly lower elevation than the non-degraded tussock areas ((136.36 ± 0.11) m). This indicates that degraded tussock areas experienced longer flooding durations. Morphological characteristics indicated that with increasing degradation degree, tussocks gradually became shorter and smaller, and their shapes tended to become increasingly irregular. Soil physicochemical property analysis indicated that with increasing degradation degree, the contents of soil total phosphorus (TP), soil organic carbon (SOC), total nitrogen (TN), and total carbon (TC) generally showed a decreasing trend, reflecting a loss of soil carbon and nitrogen pools. However, no significant differences were observed between lightly degraded and non-degraded tussock areas. Analysis of the impact of hydrological conditions on tussock communities reveals that both flooding conditions and flow velocity significantly affect degraded and non-degraded tussock communities, with flooding depth and duration being the key hydrological factors influencing the degradation of Carex tussock wetlands. Prolonged inundation exerts detrimental effects on tussock biomass, resulting in diminished tussock stature and structural integrity, ultimately driving tussock degradation. Concurrently, flow scouring plays a dual role in both shaping tussock morphological characteristics and accelerating degradation processes through synergistic interactions with inundation stress. Additionally, the ecological feedback of degraded tussocks further exacerbate Carex wetland degradation. This study provides a theoretical basis for the protection and restoration of Carex tussock wetlands, particularly in terms of hydrological regulation strategies, offering significant practical implications.