652700。 According to the query of official website, the postcode of Tonghai, Yuxi, Yunnan is 652700. Tonghai County belongs to Yuxi City, Yunnan Province. It is located on the lake plain in the south-central part of Yunnan Province, bordering Huaning County in the east, Eshan Yi Autonomous County and Hongta District in the west, Shiping County and Jianshui County in Honghe Prefecture in the south and Jiangchuan District in the north, with a total area of 72 1 square kilometer.