The multibillion dollar deal was signed Saturday in Beijing by U.S. Energy Secretary Samuel Bodman and senior Chinese planning official Ma Kai.
Bodman says the project will create about 5,500 jobs in the United States and will help narrow the huge U.S. trade deficit with China.
Under the agreement, Westinghouse will build four nuclear reactors at two sites in China: the eastern city of Sanmen in Zhejiang province, and the southern city of Yangjiang, in Guangdong province.
Westinghouse president and chief executive Stephen Tritch says the company hopes to have the plants operational by 2013.
China is building scores of new nuclear power plants, with the help of technology from overseas companies, in a bid to sustain its energy-hungry economy.
Westinghouse was acquired earlier this year by Japan's Toshiba Corporation. The Pittsburgh-based company was competing for the lucrative Chinese contract with French nuclear group AREVA and Russia's AtomStroyExport.