Prof Xu graduated in Astrophysics division of Geophysics Department of Peking University in 1987. In 1988, he entered Astronomy Department of Columbia University through the China-US Physics Examination and Application program (CUSPEA), and obtained Doctoral degree in 1993. After PhD, he served as a post-doctoral researcher for three years in the Mechanical and Aerospace Engineering Department of Princeton University. He joined HKUST in 1996 and is currently chair professor of Mathematics Department. Since 2008, he was Changjiang visiting professor of Peking University. His research mainly concentrates on the numerical algorithm development for the computational fluid dynamics. The gas-kinetic schemes developed in the past twenty years have been successfully used for the rarefied and continuum flow computation. Currently, he served associated editors for Communications in Computational Physics, International Journal of Computational Fluid Dynamics, and Computers and Fluids.