In the hydro-fluctuation belt of the Three Gorges Reservoir Area (TGRA), plants are subjected to a long period of flooding which can affect their growth and survival. In additional, when the flooding recedes, plants may experience drought stress that can also affect their growth and photosynthesis. Thus, screening for suitable species that can survive these fluctuating conditions is necessary for the successful restoration of vegetation to the hydro-fluctuation belt of the TGRA. Hemarthria altissima, a plant commonly found in the TGRA, may be one such suitable plant in the remediation process of the hydro-fluctuation belt. H. altissima has a high survival rate and is well adapted to flooding; however, the response of these plants to drought following flooding and the physiological mechanisms behind this response are unknown. In order to characterize these mechanisms, we studied leaf gas exchange, stomatal limitation (L_s), and water use efficiency (WUE) in H. altissima under different water regimes in the hydro-fluctuation belt of the TGRA. We applied the following six water regimes:control (CK, soil water content 60%-63% of soil water field capacity), soil surface flooding (SF, with water level 5 cm above the soil surface), total flooding (TF, with water level 1 m above the soil surface), control-drought (CD, control group followed by drought treatment), soil surface flooding-drought (SFD, soil surface flooding followed by drought) and total flooding-drought (TFD, total flooding followed by drought). Net photosynthetic rate (P_n), transpiration rate (T_r), L_s, and WUE of H. altissima in the SF and TF groups were significantly lower than that in the control group, whereas the intercellular CO₂ concentration (C_i) in SF and TF were significantly higher than in the control group after the end of flooding stress, which indicated that the decrease in P_n may be attributed to non-stomatal limitation. Under drought stress, P_n, G_s, and T_r in groups CD and SFD were significantly lower than in the control group, whereas in TFD, they showed no significant differences to the control after the end of drought stress. In contrast to the SF and TF groups, C_i in the CD, SFD, and TFD groups was slightly lower than that in the control group. However, L_s in the CD, SFD, and TFD groups increased under drought stress, indicating that stomatal limitation could be the main cause of the decline of P_n. WUE in the CD, SFD, and TFD groups was significantly higher than in the control group, indicating H. altissima coped with water stress by increasing WUE. By the end of the recovery period, the P_n, G_s, C_i, T_r, L_s, and WUE of the SF, TF, CD, SFD, and TFD groups showed no significant difference to those of the control, indicating that H. altissima can adapt to flooding followed by drought stress. Previous flooding did not affect the subsequent sensitivity of H. altissima to drought. This characteristic of H. altissima is beneficial to its potential survival when transplanted to the hydro-fluctuation belt of the TGRA.