Controversy over quick or slow building of "Three Gorges Project" in Yangtze River have lasted over 30 years. The reasons of a few people who vigorously hold building the project are these to emphasize benefits right before eyes and of a few aspects, such as generating electricity, retaining flood and openning navigation, but that neglects the submergence loss, emigrant in a large amount, sedimentation, bringing out earthquake, geology calamity, ecological disaster and cultural relics destroy, etc.. However, most of scientists advocating to put off the "Three Gorges Project" analysed the environment of the Three Gorges Area and all of the Yangtze River Valley, drawn the lessons at all time and in all countries, and considered the special condition and ability in economy of our country. Meanwhile, they take the international struggling situation into full account after having quoted a vast amount of investigation data.