In 1979, the United States changed its diplomatic recognition of China from Taipei to Beijing. In the U.S.-People’s Republic of China Joint Communique that announced the change, the United States recognized the Government of the People’s Republic of China as the sole legal government of China and acknowledged the Chinese position that there is but one China and Taiwan is part of China. The Joint Communique also stated that within this context the people of the United States will maintain cultural, commercial, and other unofficial relations with the people on Taiwan.
The United States does not support Taiwan independence. Maintaining strong, unofficial relations with Taiwan is a major U.S. goal, in line with the U.S. desire to further peace and stability in Asia. The 1979 Taiwan Relations Act provides the legal basis for the unofficial relationship between the United States and Taiwan, and enshrines the U.S. commitment to assisting Taiwan in maintaining its defensive capability. The United States insists on the peaceful resolution of cross-Strait differences and encourages dialogue to help advance such an outcome. The United States currently has interests residing in the American Institute. For more information on the ambassador and the U.S. relationship with Taiwan, click here.
Source, United States, Department of State, Bureau of East Asian and Pacific Affairs