Houhai is located in the Xicheng District of Beijing city center, Houhai is an integral part of Shichahai, composed of Qianhai, Houhai, Xihai three water surfaces, in order to be different from Beihai, Zhonghai, and South China Sea "first three seas", known as "back three seas". Houhai East from Di'anmen Outer Street, West to Xinjiekou Street, South to Ping'an Street, North to North Second Ring Road, the total area of 146.7 hectares, of which 34 hectares of water area,11.5 hectares of green space. This is the ancient waters of the Yuan Dadu period 700 years ago in Beijing.