This paper focuses on the background and meaning of Taiwan’s anti-Communism policy and the mainland recapture plan in the early 1950s. After Nationalist government retreated to Taiwan, the survival of the Kuomintang government was uncertain. In order to survive, Taiwan’s Nationalist government desperately needed international recognition and support. But the United States declared not to intervene in China’s civil war and gave up Taiwan. The protection and assistance of the United States was imperative to the survival of Taiwan, but the United States was indifferent to it. Taiwan and other Asian countries tried to conclude collective security system in order to ensure the safety, through which Taiwan anticipated to draw attention and aid of the United States. It was the Korean war that helped Taiwan to escape from the crisis of survival. The war itself was threatening to the survival of Taiwan as well as South Korea. The Korean War, however, paved way for the interest and the eventual intervention of the United States in the affaire of Taiwan. Under the auspices of the United States, Taiwan could solve Chinese representative problem of the UN and the Taiwan’s international position. Because of power imbalance between Taiwan and mainland China, Taiwan had to admit that she could not put a recapture of the mainland plan into practice. Instead, Taiwan actively tried to build a regional security system for the purpose of nation survival. Taiwan wished that a regional security system got a foothold for a recapture of the mainland plan. Since Taiwan and Korea seemed to be of like minds in terms of anti-Communism and were in similar circumstances, two countries maintained the mutually cooperative relationship, and Taiwan used it to promote the recovery of the mainland plan. Taiwan made vain effort to conclude an offensive and defensive alliance with South Korea to jointly fight China proper and North Korea, which was not realized because of the opposition from the United States and the passivity of South Korea and Southeast Asia. In the Cold War era, the role of the United States in the national survival of East Asia was critical. Taiwan tried to establish a regional collective security system in Asia and carry forward the mainland recapture plan for the purpose of ensuring the survival and security. Since it was contrary to America’s policy of the East Asia, Taiwan’s policy was not executed. However, Taiwan’s actions were able to get the attention of the United States. It was in American regional interest in East Asia to protect and contain Taiwan in bilateral mutual defense treaties than allowing Taiwan to assume aggressive stance towards the mainland China and to increase instability in the region. In conclusion, Taiwan had to give up the mainland recapture plan. Instead Taiwan could secure nation survival and security. In the 1950s, Taiwan’s anti-Communist policy and the mainland recapture plan were the crucial alternatives for her existence. One can say that Taiwan was successful in surviving in some degree.