Born in 1963 in Wenzhou, Zhejiang Province. In September 1979, he entered the Department of Mathematics of Fudan University without examination. In 1989, he received his doctorate from the University of California, Los Angeles (UCLA). In 1991, he ended his two-year visit to Northwestern University and began to work at Peking University. In 2001, he won the "Cross Century Talent Fund" of the Ministry of Education, the National Outstanding Youth Project in 2006 and the special government allowance in 2012. He is currently the dean of School of Mathematical Sciences, Peking University.

The research field is Markov process; The phase transition and critical phenomena of infinite particle systems on trees and graphs are studied. The metastability of stochastic Ising model is characterized and extended to a family of Markov chains with exponential perturbation; The large deviation theory is introduced to make the treatment method unified and concise, and the application scope is wider; The random walk in random environment is studied, and the upper and lower bounds of the velocity of the random walk are obtained; It is proved that the conclusion that the velocity of random walk is zero remains unchanged under random disturbance.