The International Astronomy Olympiad (IAO), the International Olympiad on Astronomy and Astrophysics (IOAA) and the Asia-Pacific Astronomy Olympiad (APAO) are three international astronomy Olympiads. As the only authorized unit in China, Beijing Planetarium has organized teams to participate in various international astronomy Olympiads, and made great achievements. International astronomy Olympiads are divided into theory round, observation round and data analysis round, which investigate all kinds of quality of participants. Among them, the theory round is about the understanding and application of astronomy; the data analysis round simulates the astronomical scientific research that the participants need analyze and draw conclusions through the given observation data; the observation round comprehensively inspects the students' cognition of the starry sky through the actual observation, the star recognition in the dome, the analysis and description of the star map, and operation of telescope.