In 1937, Xing returned to China. He moved to Kunming since eastern China was occupied by Japanese invaders. There, he spent some efforts on the refining of Quinine. Then Xing joined the New Fourth Army as a teacher in its military medical school. Moreover, he assisted the army to product medicine.
In 1946, Xing went back to Beijing and accepted an appointment as a professor at Peking University.
In 1950s, Xing designed a new method to synthesize the chloramphenicol.
During 1964–65, Xing participated in the total synthesis of bovine insulin project, co-operating with Shanghai Institutes for Biological Sciences.
In 1980, Xing was elected as an academician of the Chinese Academy of Sciences.
During 1981–87, Xing focused on the activation methods for the carboxyl group in the peptide synthesis, and developed related chemical reagents.