Origin and propagation have been the fundamental problems of cosmic rays ever since the discovery of cosmic rays a century ago. Extensive air shower (EAS) arrays can directly sample the cosmic ray shower particles that reach the observation altitude. They are wide field of view (FoV) detectors able to view the whole sky simultaneously and continuously. The last generation high altitude EAS experiments at Yang Ba Jing observatory were successful in gamma rays and cosmic rays observation. The Large High Altitude Air Shower Observatory (LHAASO) project is a new generation hybrid instrument, to be built at 4410 meters of altitude in the Sichuan province of China. The aim is to study with unprecedented sensitivity the energy spectrum, the composition and the anisotropy of cosmic rays in the energy range between 1012 and 1018 eV, as well as to act simultaneously as a wide aperture (one stereo radiant), continuously-operated gamma ray telescope in the energy range between 1011 and 1015 eV. The status and the prospect of LHAASO will be presented.

Yi Zhang is an experimental physicist at IHEP ( Institute of High Energy Physics) Chinese Academy of Sciences. He received his Ph.D at IHEP in 2008. As the main contributor, he obtained the two-dimensional high-precision cosmic-ray anisotropy map for energies from a few to several hundred TeV by improving the all-sky survey method. As a group leader, he developed the ultra-wide-of-view air Cherenkov telescope and built the Yangbajing hybrid array. He recently works as the director of Yangbajing observatory as well as one of the leaders of LHAASO gamma-ray physics group and of muon detector group. His major interests are high- energy gamma-rayastronomy and cosmic-ray physics.