Poyang Lake is the biggest freshwater lake in China,where water level and surface area are crucial parameters to the lake ecosystem.This paper studies into the mathematical relationship between water level and area of Poyang Lake,with purpose to estimate the lake area by water level through model simulation.The EFDC(Environmental Fluid Dynamics Code) hydrodynamic model is used to simulate the daily variation of Poyang Lake area in typical hydrologic years.Then the statistical relationship functions are developed between simulated surface area and actual water level data which were collected from four hydrologic observation stations including Kangshan,Tangyin,Duchang and Xingzi.Furthermore,the statistical relationship is verified by remote sensing data.The results indicate that the water level and area of Poyang Lake are highly dynamic during typical hydrologic years,yet the EFDC based method can estimate the Poyang Lake area with relatively high accuracy,with the average relative error being 4.14%.