During the Sino-Japanese War and the Chinese Civil War, Wu served on several military commissions in Northwest and Northeast China, where he was responsible for liaison and military coordination programs. After the PRC was established in 1949, he became director of the USSR and Eastern Europe Department of the Ministry of Foreign Affairs, in which capacity he accompanied Foreign Minister Zhou Enlai to Moscow in February 1950 to negotiate the Sino-Soviet Treaty. In November 1950 Wu, as the PRC's special envoy, attended a United Nations (UN) Security Council meeting in which he condemned U.S. Korean War measures in the Taiwan Strait, calling them an invasion of Chinese territory. In 1955 he became the vice foreign minister, a position he held until March 1955, when he was appointed Chinese ambassador to Yugoslavia. He returned home in late 1956 and became a member of the CCP Central Committee and in March 1959 became director of the party's International Liaison Department. He held both posts until the mid-1960s, during which time he led a number of delegations abroad, primarily to communist bloc countries.
In 1966 during the Cultural Revolution, Wu was purged from the government and imprisoned. In 1975 he returned to the public scene, first as deputy chief of the PLA General Staff. In 1980 he was named director of the Beijing Institute for International Strategic Studies and was also named vice foreign minister, in which capacities he played an active role in enhancing the PRC's international status. Wu died on 9 November 1997 in Beijing.
Ma, Jisen. The Cultural Revolution in the Foreign Ministry of China. Hong Kong: Chinese University Press of Hong Kong, 2004.; Ross, Robert S., ed. China, the United States, and the Soviet Union: Tripolarity and Policymaking in the Cold War. Armonk, NY: Sharpe, 1993.