CARS has carried out observation on permafrost of Qingzang Plateau for over 40 years since 1960s, and has undertaken 33 technology tackling subjects and comprehensive testing projects, implemented a lot of technical service in aspects of environmental protection supervision, project quality inspection, etc., participated in the whole engineering and construction of the whole line in a comprehensive way, and provided technological support for solving three international challenges as “fragile ecology, environment of high altitude, low temperature and oxygen insufficiency, permafrost”