The main objective of the Astronaut System is to ensure the health and performance of astronauts during long term space flight, highlighting the combination of medicine with engineering. The primary tasks of the Astronaut System include astronaut training, astronaut support and human space life science research. The purpose of the astronaut training is to establish a competent Astronaut Corps with excellent conduct, rational structure and appropritae scale, to select and train qualified crew for human spaceflight missions. Astronaut support refers to the construction of the health support system, the living support system and the work support system, setting the medical/ergonomic requirements for human-rated spacecraft and implementing the evaluation, thus providing support for astronauts during orbital flight. Human space life science research refers to the exploration and solution of space life science issues related to human being, developing advanced health support and human factors engineering technologies, so as to provide sustained theoretical and technological support for innovative development of manned spaceflight and future human deep space exploration.