The Purple Mountain Observatory (Zijinshan Astronomical Observatory) is the most well-known observatory in China. Situated on the third peak of the Purple Mountain, the observatory was established in 1926 and is now under direction of Chinese Academy of Sciences. It has been listed as one of the highest ranking research institutions for astronomy and space sciences since then. It also opens to public as a tourist destination.

As the significant light pollution from nearby urban areas, the observatory moved to Xuyi, a remote county town in Xuzhous jurisdiction in the north of Jiansu. The present address of the observatory is only used as offices and other facities or used for tourism.

The Purple Mountain Observatory has helped scientists in making many significant discoveries of astronomic objects. They include the periodic comets 60P/Tsuchinshan and 62P/Tsuchinshan, the non-periodic C/1977 V1 (Tsuchinshan), Comet 1977X and more than 147 asteroids such as the Trojan asteroids 2223, Sarpedon, 2260 Neoptolemus, 2363 Cebriones, 2456 Palamedes and the eponymous 3494 Purple Mountain.