The lake area of Jianghan Plain,which is prone to a floods and droughts,is the major grain-producing district and an economic core area of Hubei province.In view of the fact that Jianghan Plain is vulnerable to sudden changes in droughts and floods,this paper takes the five major lakes of Long Lake,Hong Lake,Liangzi Lake,Futou Lake and Diaocha Lake as examples,the methods of dispersal chart and diachronic guarantee curve are used to determine the flood season of Lake area,and then to determine the lake control water level in different periods so as to improve the utilization of rain and flood resources.