In the light of storm flood properties, analysis and computation ave carried out about four heavy flood events ever occurred in the Poyang Lake area using four mbthods, i.e.area ratio method, adjusted total inflow method, tingle-source model(the current flood forecasting scheme) and the Xin'anjiang Model(three-source), for the sake of river basin flood control planning The effect of the changing ratios of water surface to land surface corresponding to diferent water stag-es on i.e off generation and flow concentration is analyzed.and the estimation formulae in the Xin'an jiang Model are modified.Results show that conceptual rainfall-run of models can properly simulate the flood processes, and that under reasonable conditions, simplified methods can also prod uce satisfied results.The applicability co nditions of different methods are given through com-parative analysis.