The archaeological site of Huating, located in the southwestern part, was inhabited as long as 5,000 years ago. During the
Zhou dynasty, its southern territory was dominated by a minor state: Zhongwu, which was variously annexed to
Wu,
Yue and
Chu. Two counties designated Siwu and Jianlin were established in its southern part and northern part in the West Han, both counties were dissolved during the Southern and Northern dynasties, and the major region was administrated by
Suqian. The borders among then Suqian,
Shuyang,
Donghai along with
Pizhou were merged and became a separated county in 1949. It named after the seat, Xin'an () town, but was renamed Xinyi, a river flowing through its area, in 1952, because of
its namesake in Henan. The county was converted to a county-level city in 1990. ==Administrative divisions==