At present the international research emphasis of lake water environment has turned to study ecosystem management of lake basins. That is,we should be from a watershed scale point of view to control pollution, remedy ecology, manage ecological system and to carry out a sustainable harmonious development among society, economy and ecosystem health in lake watershed. This paper put forward the management concept framework of ecological diversion water based on the definition of ecological diversion water in the Dongchang Lake watershed. This paper also put forward an optimized model of the harmonious development between society and economy in the Dongchang lake watershed and an environmental management system of water quality, water quantity guarantee and habitat improvement. It includes ideas and concepts of watershed management, water environmental management and ecological system management.