Since the withdrew of the Republic of China withdrew from the United Nations in 1971, the Nixon's visiting to Peking in 1972, and followed by the normalization of relations between Japan and the Chinese Communists, those impacts on international situation made many alliances to server diplomatic relation with the Republic of China. In the beginning of 1979, there were merely over 20 nations to maintain the diplomatic relations with the Republic of China, which 12 nations were in Latin America. If those Latin America alliances were affected by the United States to support Peking authority, the Republic of China could be much isolated in the international community. Fortunately, the strong anti-communism stance of the President of the United States Ronald Reagan changed such isolated situation. By the cooperation with the United States and its assistance, it enhanced the diplomatic relations among the Republic of China and Latin America alliances.The United States played a very important role in foreign relations among the Republic of China and Latin America alliances. In 1981, due to the firm anti-communist stance of the Reagan administration, the Republic of China cooperated with the U.S. Reagan administration against communism. By the material assistances provided by the United States, and anti-communism experiences with political warfare training provided by the Republic of China, these two nations jointly combat communism in Latin America, which protected the safety of the American backyard. For the Republic of China, the diplomatic relations among Latin America alliances not only broke diplomatic predicament, but also own the support of the United States to be its anti-communism ally. This period of history in the development of diplomatic relations of the Republic of China should be commemorated.