The Chinese National Astronomy Olympiad (CNAO) was initiated in 2003. Organized by the Chinese Astronomical Society and hosted by the Beijing Planetarium, it has been running for over two decades. Since 2019, it has been officially recognized by the Ministry of Education of the People's Republic of China, as a national competition for primary and secondary school students. The competition aims to stimulate students' interest in astronomy, promote astronomy education in schools, and identify candidates for China's International Astronomy Olympiad teams. It also serves as a reference for cultivating domestic astronomical talent and for university astronomy program recruitment. The CNAO has now become a vital platform for fostering scientific literacy and discovering promising young talent in astronomy.