The Three Gorges Project (TGP) is a landmark Chinese hydroelectric project with the goal of harnessing the Yangtze River and developing its water resources. Because of its enormous size and far-reaching influence, the project’s impact on the Yangtze River’s original ecological environment has been a concern to many people. This article examines the environmental effects of TGP with regard to reservoir-induced seismicity and bank stability, climate changes, sedimentation and bank erosion, the protection of aquatic species and water quality, and resettlement. Based on the operation monitoring data of TGP in 10 years (2003—2012), this article analyzes the tendency of reservoir-induced seismicity and bank stability, developing trend of sedimentation and bank erosion, the interplay between climate change and TGP, the distribution and cause of water contamination, the situation of aquatic species’ protection and living situation of resettled residents. At the same time, this article lists the comprehensive benefits of TGP in flood control, power generation, shipping, water supply, energy conservation and emission reduction. In the end, the authors deem that there is a dynamic and harmonious relationship between humankind and nature. The cognition about TGP will be progressed in practice, and harmonious relationship between the environment and TGP will be achieved through more practice.