Dr. Wang Xiangyu is a professor at the School of Astronomy and Space Science in Nanjing University, China. He got his PhD degree in 2001 from Nanjing University. He was a postdoc at Penn State University from 2005-2007, and then was a visiting scientist at the Max-Planck Institute of Nuclear Physics, the Wezimann Institute of Israel etc. His research interests are mainly in the origin of high-energy cosmic rays, neutrinos and gamma-ray bursts.Cosmic rays are extremely energetic charged particles with energy up to 1020 eV. Although these particles have been discovered for more than 100 years, the astrophysical sources of them are still unknown. As cosmic rays produce secondary neutrinos and gammarays within the source or during the propagation, neutrino and gamma-ray are important messengers to study the origin of the parent cosmic rays. In recent years, a lot of progress has been made in this area, thanks to IceCube, Fermi and IACT telescopes. I will discuss the multi-messenger approach, incorporating gamma-ray, neutrino and cosmic ray research, in studying the origin of Galactic and extra-Galactic cosmic rays.