Abstract:In order to understand the plant community structure in wetlands of Poyang Lake, the species-area relationship of three kinds of marshland plant communities were studied. The plant species number was investigated by nested plot method, and the species-area equations were fitted with 3 unsaturation curves. The results showed that based on the actual data, the number of the species rapidly increased at first with increment of sampling area, and then gradually became stable latter on. The size of 30 m2 was determined as the minimum sampling area for the plant community. The fit effects of power function model on species-area relationship among 3 studied communities were the best with RSE of 0.35, 0.35, 0.56, AAD of 0.23, 0.17, 0.35 and AARD of 0.06, 0.02, 0.07, respectively; while those of exponential model and Fisher model were ordinary. Compared with the measured data, the minimum sampling areas under different scaling factors for 3 studied communities calculated by exponential model were the fittest to the actual situation. These would provide theory references for sample establishment in data collection of plant community in Poyang Lake Region.