After the end of World War II, he served as vice director of the science committee of UNESCO, under director Joseph Needham. After the founding of the People's Republic of China in 1949, Ye moved to China in 1950 with his wife Marcelia and their one-year-old son. He was elected a founding member of the Chinese Academy of Sciences (CAS) in 1955. In 1958, he established the Institute of Chemical Metallurgy (now Institute of Process Engineering) of the CAS and served as the founding director. In addition, he recruited Chen Jiayong to help develop hydrometallurgy at the institute. After examining the shortcomings of China's steel industry, Ye suggested the application of the "three high method": high pressure, temperature, and humidity, and Shijingshan Steel built a test furnace according to his specification. He also solved key technical problems at Panzhihua Iron and Steel and Baotou Steel. He published more than 100 papers and won multiple State Science and Technology Prizes. However, many of his far-sighted proposals were not adopted at the time. He advocated the development of oxygen converter process for steelmaking, but others insisted on building large open hearth furnaces, a technology that was becoming obsolete. He advocated the use of computers for metallurgical research, and was ostracized by those who could not understand the connection. In 1952, he proposed simultaneous mining of iron ore and rare earths at the Bayan Obo mine, whereas Soviet experts preferred to focus on iron ore only. The Chinese government adopted the Soviet proposal, and only came to fully realize the value of the rare earth resources of Bayan Obo decades later. Ye was elected a member of the 2nd and 3rd National Committee of the Chinese People's Political Consultative Conference (CPPCC). In 1964, he was elected a Standing Committee member of the 3rd National People's Congress. When the Cultural Revolution erupted in 1966, however, he was persecuted and imprisoned by the Red Guards. He spent the final five years of his life in custody, during which time he wrote technical papers and proposals totaling 200,000 words. He suffered from colon cancer and died in prison on 24 November 1971. Ye was posthumously rehabilitated after the end of the Cultural Revolution and recognized as the founder of chemical metallurgy in China. On 10 July 1978, a grand ceremony was held for his interment at the Babaoshan Revolutionary Cemetery in Beijing. Vice Premier Fang Yi, who presided over the ceremony, declared him the "People's Scientist".