Functional traits of plants determine their capacity to utilize resources and respond to the external environment. The water-level fluctuation zone of the Three Gorges Reservoir area exhibits significant variations in habitats at different elevations due to various flooding intensities. Therefore, conducting research on the ecological strategies and differences in functional traits of plant communities in the water-level fluctuation zone under different flooding gradients is crucial. This research will provide a comprehensive understanding of the mechanisms howplants adapt to diverse habitats in the water-level fluctuation zone. In this study, we selected the Pengxi River basin, which is affected by changes in water levels due to the Three Gorges Reservoir. We analyzed the plant communities and their functional trait indexes under varying intensities of flooding along the elevation gradient. The results showed that: (1) the plant communities in the water-level fluctuation zone were in the primary stage of succession and there was significant differentiation of plant communities under different flooding gradients. (2) Environmental stress was the main factor determining the ecological strategy of the plants in the water-level fluctuation zone, which showed a more concentrated S-type strategy in general, and there was a trend of gradual transition to a R-type strategy as the elevation increased. (3) With the increase of elevation, the plant's height, the stem dry mass content, specific root length, and leaf tissue density tended to increase, while the specific leaf area decreased. (4) The functional traits were significantly correlated with each other and adapted to habitats with varying intensities of flooding disturbance by forming unique combinations of traits. On the one hand, the lower part of the water-level fluctuation zone was more likely to allocate resources to leaf production, allowing plants to rapidly acquire resources and complete their life history during the emergence period. On the other hand, the upper part tended to invest in defense tissues and root systems to withstand drought. The findings of this study can serve as a theoretical foundation for biodiversity conservation and ecosystem restoration in the water-level fluctuation zone.