<Li> Liu Chieh (last) </Li> <P> The Republic of China (ROC) was a charter member of the United Nations and one of five permanent members of the Security Council until 1971 . The ROC joined the United Nations as a founding member on 24 October 1945 . </P> <P> The "Big Four" victors of World War II (Nationalist China, the Soviet Union, the United Kingdom, and the United States) were the founding members of the United Nations that drafted the United Nations Charter in 1944, which was ratified on 26 June 1945 by the representatives of 50 countries . China, in recognition of its long - standing fight against aggression, was accorded the honor of being the first to sign UN Charter . President Franklin Roosevelt had acknowledged China's war effort in World War II and stated his desire to allow China to "play its proper role in maintaining peace and prosperity" in the world . Thus, despite opposition from other leaders, especially Winston Churchill, China became a permanent member of the Security Council from its creation in 1945 . </P> <P> In 1949, the Communist Party of China won the Chinese Civil War in mainland China and established the People's Republic of China (PRC), claiming to be the sole legitimate government of China . The ROC government retreated to the island of Taiwan (which it gained control of in 1945 at the end of hostilities in WWII), Quemoy Island, and the Matsu Islands . Until 1991, the ROC also actively claimed to be the sole legitimate government of China, and during the 1950s and 1960s this claim was accepted by the United States and most of its allies . While the PRC was an ally of the Soviet Union, the U.S. sought to prevent the Communist bloc from gaining another permanent seat in the Security Council . To protest the exclusion of the PRC, Soviet representatives boycotted the UN from January to August 1950, so they didn't veto the intervention of UN military forces in Korea . </P>

When did china become permanent member of un security council