Sun Yisui graduated from the Astronomy Department of Nanjing University in 1958, and he was elected an academician of the Chinese Academy of Sciences in 1997. Currently, he serves as a deputy director of Mathematical Department of the Chinese Academy of Sciences, a member of the Department of the Chinese Academy of Sciences Scientific Moral Construction Committee, one of the conveners of the National Postdoctoral Management Committee (physics and astronomy), and a member of Expert Advisory Committee of Department of Mathematical Sciences of National Natural Science Foundation of China. He is also an honorary professor or adjunct professor at many colleges and universities.

He used to be the dean of the Graduate School of Nanjing University, a member of the Disciplinary Committee of Celestial Mechanics of the International Astronomical Union, a chief scientist of the National Climbing Plan for the “Ninth-Five Year” and Key Basic Research and Development Plan for the “Tenth-Five Year” ("973" Plan), a convener of the Disciplinary (Physics, astronomy) Appraisal Group of Academic Degrees Committee of the State Council.

Sui Yisui’s research focuses on celestial mechanics and nonlinear dynamics, and he has published more than 90 papers in important journals at home and abroad, published two monographs, and compiled two books and two international conference proceedings.

He has made many academic achievements. Together with his collaborators, he has proved that the maximal lower bound of the moment of inertia corresponding to the Euler particular solution of the three-body problem is the maximal lower bound of the moment of inertia of all bounded motion. For a given three-body position, this solves the problem of the range of the trisolaran orbit shape and spatial position. He first found that there is sufficient two-dimensional invariant torus in the near-integrable three-dimensional volumetric mapping of conservative systems, and then he and his collaborators gave strict mathematical proof for this result.

From this result, two well-known hypotheses can be rejected: the quasi-ergodic hypothesis of the conservative system and the hypothesis of the positive Lyapunov exponent of Pesin. This finding has been valued and cited by world-class scholars and has had a far-reaching impact on nonlinear dynamics and fluid mechanics.

Since 1978, he has won the second prize of the National Natural Science Award once, the first prize of the Chinese University Science and Technology (Natural Science) Award once, the first prize of the Major Scientific and Technological Achievements of Jiangsu Province once, and the second prize of the National Science and Technology Progress Award of the Ministry of Education for four times. He also received the Ho Leung Ho Lee Foundation Science and Technology Progress Award and the Second-Session China Publishing Government Award Book Award and other commendations and awards. The International Astronomical Union (IAU) has named the asteroid No.185640 Sun Yisui Asteroid.