The dam was originally envisioned by Sun Yat-sen in The International Development of China, in 1919.It was stated that the construction of a dam capable of generating 30 million horsepower (22,371 MW of electricity) was possible downstream of the Three Gorges.In 1932, the Nationalist government, led by Chiang Kai-shek, began preliminary work on plans for a dam in the Three Gorges. Then, in 1939, Japanese military forces occupied Yichang and surveyed the area. A design, the Otani plan, was completed for the dam in anticipation of a Japanese victory over China.In 1944, involvement from the United States began when the then Bureau of Reclamation chief designing engineer, John L. Savage surveyed the area and drew up a dam proposal for the 'Yangtze River Project'. Around 54 Chinese engineers were sent to the U.S. for training. Some exploration, survey, economic study, and design work was done, but the government, in the midst of the Chinese Civil War, halted work in 1947.
After the 1949 communist victory, the leader Mao Zedong supported the project, but the Gezhouba Dam project was begun first, and economic problems including the Great Leap Forward and the Cultural Revolution slowed progress. In 1958, after the Hundred Flowers Campaign, some engineers who spoke out against the project were imprisoned.
During the 1980s, plans were revived. The dam was approved by the National People's Congress in 1992: out of 2,633 delegates, 1,767 voted in favour, 177 voted against, 664 forfeited, and 25 members did not vote.The construction started on December 14, 1994.