After graduating from Shanghai Medical School, now Shanghai Medical College, Fudan University, in 1952, Zeng decided to pursue virology research because diseases caused by viruses, such as cholera and polio, posed a threat and people had limited understanding and medical treatment.

In 1984, Zeng took the lead in HIV research in China. Through epidemiological investigation and experiments, he proved that the virus first came to China from the U.S. through blood products to treat hemophiliac patients during 1982-1984. Three years later, he isolated China's first HIV-1 strain and established a rapid diagnostic test.

In addition to scientific research, Zeng put considerable efforts into HIV/AIDS education and intervention. Along with other experts, he wrote to the State Council three times, offering advice on prevention and treatment of AIDS in China.