During the Second Sino-Japanese War, he served as political commissar of the First Division and commander of the Fifth Division, among others. In the Chinese Civil War, he initially served as Deputy Commander Northeast and was later active in capturing Guangdong and Hainan.
In 1950, Deng Hua became the First Deputy Commander of the Chinese People's Volunteer Army and was the main assistant of Marshal Peng Dehuai. In July 1951, he was involved in the military negotiations to stop the war, and after the failure of the negotiations, he proposed changes to the Sixth Campaign Plan, a proposal that was adopted by Chairman Mao Zedong. When the American-led UN forces launched the "Autumn Offensive", Deng commanded the Volunteers to win a major victory. After Peng Dehuai returned to China in 1952, he served as the commander and political commissar of the PVA, and commanded the counterattack in the fall of 1952, that led to the signing of the Korean Armistice Agreement in 1953.
In 1959 he was removed from the PLA as a close associate of Peng Dehuai. He then served as the director of mechanized agriculture in Sichuan from 1960 until 1977. During the early Cultural Revolution he was criticized but accusations against him were withdrawn in 1968. In 1977, after the end of the Cultural Revolution, Deng was completely rehabilitated and restored to his military rank, and also became Vice President of the Chinese Academy of Sciences.
He died in Shanghai on July 3, 1980, at the age of 70. In his official obituary the CPC Central Committee praised him highly: "Comrade Deng Hua was loyal to the party and loyal to the people, adhering to the Party's correct line. He was an outstanding member of our party, an excellent military commander and political worker".