Abstract：The construction of TGP will have a deep effect on the evolution of regional systems. The problem should be disscussed. The vast Dongting lake plainand Jianghan plain on the middle Yangtze river are near the Three Gorges reservoirarea. The floods coming from the upper Yangtze river have been retarding the processes of spatial development in the area. However, the opportunity of rationalization of spatial structure has arisen owing to the construction of TGP. This papertries to show the interaction mechanism between the key external environmentalfactors and the regional system changes using the system theory and the spatialstructure theory. It is the trigger of regional system evolution to change the qualityof external entropy flow resulting from environmental transformation with the aimsat promoting what is beneficial and bolishing what is harmful, and the changes willaccelerate the harmony man-environment relationship. The construction of TGP isthe strategical turning point of development of the economic zone of the Yangtzeriver. The implementing strategy and starting ahead will accelerate socio-economicdevelopment in the Dongting-Jianghan plain.
