Tunchang County is a county of Hainan Province, People's Republic of China. Its postal code is 571600, and in 1999 its population was 250,059 people. The administrative seat lies at Tuncheng.

Tuncheng is a town and the administrative seat of Tunchang County in Hainan, China. It lies along the G224 highway, about 80 kilometres from Haikou. The town is characterized by a number of botanical gardens with water features. There are also crystal mines in Tunchang. In 1992 the town had a population of 14,974 people living in 78 villages.