Su Dingqiang was born in June 1936. He graduated from the Department of Astronomy at Nanjing University in 1959 and served as a teaching assistant at the department from 1959 to 1962. From 1962 to 2003, he worked at Nanjing Institute of Astronomy and Optical Technology affiliated with the National Astronomical Observatory of the Chinese Academy of Sciences, and there, he participated in the development of many astronomical instruments such as the 2.16-meter telescope.

Since he was transferred to Nanjing University in 2003, he has worked as a professor, doctoral supervisor at the Department of Astronomy at the university and as a research fellow at Nanjing Institute for Astronomical Optics and Technology. He served as president of the Chinese Astronomical Society from 2002 to 2006, chairman of the 9th Commission of the International Astronomical Union (IAU) from 2000 to 2003, and a deputy to the 8th and 9th National People’s Congress. He was elected a fellow (academician) of the Chinese Academy of Sciences in 1991.

He once taught Basics of General Relativity and Introduction to Cosmology.

His main research area is big telescope. In the study of telescope optics, he has come up with many new ideas, optical systems, and a series of new folding axis systems and trans-prism correctors. He and Wang Ya’nan worked together and co-established a special optimization program of the optical system.

He took the lead in developing China's first Lyot birefringence filter, proposed the idea of using active optics to produce an optical system with surface changes that cannot be achieved according to traditional concepts, and he played a leading role in developing China's first active optical experiment system. In cooperation with Wang Suiguan, he presented a preliminary plan for the large-area multi-target optical fiber spectral telescope (LAMOST), one of the national major scientific projects, which has been successfully developed.

Su has published 70 papers and won the first prize of the State Science and Technology Progress Award once, the second prize of the State Natural Science Award once, and the Chinese Academy of Sciences Award four times, and in all these awards, he was the first on the name lists of the awardees.  He also won the Ho Leung Ho Lee Science and Technology Progress Award in 1999. In recognition of his contributions, the asteroid No.19366 was officially named Su Dingqiang Asteroid.