Water movement within the groundwater-soil-plant-atmosphere continuum (GSPAC) is the key to wetland eco-hydrological process research. In this paper, two typical wetland vegetation communities, the Artemisia capillaris and Phragmites australis communities were selected as study objects in Poyang Lake wetland. The HYDRUS-1D model was used to explore the GSPAC water fluxes in the two wetland vegetation communities. Besides, the vegetation transpiration and water sources of the two typical vegetation communities were clarified and compared for high (2012) and low (2013) water table years. The results showed that:(1) The annual rainfall infiltration flux at soil-atmosphere interface amounted to 1570-1600 mm, with 60% falling in the rainy season from April to June. The annual transpiration at plant-atmosphere interface totalled 346-470 mm and 926-1057 mm, respectively, for the A. capillaris and P. australis communities, with the highest values from July to August taking up 40%-46% of the annual amounts. The groundwater upward fluxes to rootzone were significantly influenced by the water table variation in different hydrological years. The annual amounts of groundwater recharge were 15-513 mm and 277-616 mm, respectively for the two vegetation communities, which concentrated in the periods with high water table and evapotranspiration rate. (2) The process of vegetation transpiration were divided into two different stages:the initial (April-June) and the main (July-October) growth stage. In the high water table year, vegetation transpiration water used in the whole growth stage can be satisfied. In the low water table year, vegetation suffered severe water stress in the main growth stage, and the actual transpiration decreased to approximately half of the potential ones. (3) The supplying water sources of vegetation communities in main growth stage were different between the high and low water table years. In the high water table year, groundwater recharge was the major water source of the A. capillaris community, while groundwater and lake water were the major water sources of P. australis community. However, in the low water table year, rainfall infiltration and antecedent soil water storage become the major water sources of the A. capillaris community, and groundwater was the major water source of P. australis community. These results help to reveal the vegetation water utilization strategy and better understand the interaction mechanism of vegetation succession to hydrological changes in wetland.