The impacts of the Three-Gorge Project are summarized in this paper from the viewpoint of the whole river basin and system ecology. Among the impacts on aquatic ecosystem and fishery of the Changjiang River basin,emphasis is placed on the survival of certain precious and rare species, such as the indigenous River Dolphin, Lipotes vexillifer. Impacts on terrestrial ecosystem include the ecological changes of the inundated, agricultural land,and the carrying capacity of the land for the resettled population in the upper reaches of the river and changes of the environment of lowland district and lowlying rice fields in the middle and lower reaches. Impacts on the surrounding geology and safety of the reservoir area include mud-rock flow,land slide and earthquake. Impacts on estuarine ecology involves increasing salination of water and soil, erosion of coastline, and the security of Shanghai city. The impacts on the cultural landscape of the Three-Gorge area are also highlighted.Through the overall and systematic analysis,the conclusion is drawn that there are both advantageous and disadvantageous aspects in the effects of the Three-Gorge Project on ecology and environment, but the disadvantageous effects are by far the greater. In order to promote what is beneficial and to reduce what is harmful,a large amount of funds has to be invested and a series of remedial measures must be taken. Further survey and studies on some of the long-term impacts which are difficult to be foreseen at present should be carried out.