The Zi Jiang (also Zishui River or Zi River; S.Chinese: 资江 or 资水; T.Chinese: 資江 or 資水; pinyin: zī jiāng; Wade-Giles: Tzu¹-chiang¹) is one of the four largest rivers in Hunan province of China, also one of the main tributaries of the Yangtze River. It is 653 km long and covers 28,2142 km² (26,728km² in Hunan).

The Zijiang has two sources, the South and the West. Originating from the norh side of Yuechengling Mountains in Ziyuan County of Guangxi, the South source, Daxishui River flows through Xinning , Shaoyang . Origination from the Huangmajie in Chengbu county , the West source, Heshui River flows through Wugang and Longhui .

The two rivers flow until they join the main river named Zijiang River at Shuangjiangkou in Shaoyang county . Then the Zijiang runs through Shaoyang, Xinshao , Lengshuijiang , Xinhua, Anhua and Taojiang , empties into the Dongting Lake at Ganxikou in Yiyang.

The four largest rivers in Hunan are: the Xiang River, the Yuan Jiang , the Zijiang River and the Lishui River.