The Large High Altitude Air Shower Observatory (LHAASO) is a major national infrastructure project for science and technology launched during the 12th Five-Year Plan period. It mainly aims to understand the origins of high-energy cosmic rays and conduct basic research on topics including high energy gamma-ray emission, evolution of astronomical objects, and dark matter distribution. The research facility was approved by the National Development and Reform Commission (NDRC) in December 2015, with a total investment of about 1.2 billion RMB and a construction period of 4 years. Located at about 4,410 m above sea level on Haizi Mountain in Daocheng, Sichuan Province, the facility is jointly constructed by the Chinese Academy of Sciences and the Sichuan Provincial Government.