Abstract: The quantitative relationships between plant communities and environmental factors in different water periods in the wetland between Le'an River and Poyang Lake were investigated in this study. Samples of aquatic plant communities, water, soils and sediments from 13 sites were investigated in April, August and November of 2012, which represented the different typical water seasons of Poyang Lake. 14 environmental factors in the water, soil and sediment samples at different sites were detected. Detrended Canonical Correspondence Analysis (DCCA) was applied to explore the relationships between aquatic plant communities and environmental factors by using Canoco for Windows 4.5 software, and the sampling site environment bi-plots were drawn based on the results of DCCA. The results indicated that 167 plant species were found in all sites within the three different water seasons, and the species composition and structure were significantly different in different water periods. In total, 33 families, 75 genera and 102 species in the normal water period, 20 families, 42 genera and 55 species in the abundant water period, and 27 families, 53 genera and 71 species in the low water period were found. The number of plant species was least in the abundant water period. The river natural environmental factors were the dominant impact factors were the dominant factors impacting the wetland plant community dynamics in the slightly polluted area in the upstream of the Le'an River. However, in addition to the impact of water level and other hydrological condition factors, the structure and species of other plant communities in the severely polluted areas were also mainly affected by pH and heavy metal pollution from copper, lead, cadmium and other factors in the soil and water environment. The plant communities in the upstream riparian were impacted by copper pollution, because they were polluted severely by heavy metals acidic wastewater. The plant communities in the middle and lower reaches were mainly impacted by the combined pollution of lead and cadmium. The DCCA ordination diagram showed the obvious response relationships between aquatic plant communities and the environment in the wetland ecosystem, and reflected the key environmental factors affecting plant communities.