After the retrocession of Taiwan in 1945, the Nationalist (Guomindang) Government adjusted the administra- tive divisions, changing the Cho to Sian (counties), Ken to Cyu (districts), and Sho to Siang (towns). This was when Sinshih Township was created. The full administrative name of the place was Sinshih Township, Sinhua District, Tainan County. In July 1946, the two Oaza of Tanding and Dashe that originally belonged to Shanshang Jhuang were moved into Sinshih Township, which was itself under the direct jurisdiction of the Tainan County Government.
The district office was originally located at No. 3, Jhongsing Street, Sinshih Village (now Sinshih District's Household Registration Office.) The office was then moved to Sinshih Elementary School activity center temporarily in 1983 when the original office building was demolished for reconstruction. In March 1984, con- struction for the new Sinshih Township Office building (No. 12, Jhongsing Street) was completed. On December 25, 2010, Taipei County, Taichung County (and City), Tainan County (and City), and Kaohsiung County (and City) were restructured and elevated to municipalities. Siang, Jhen, and Shih (townships and cit- ies) were renamed as districts while Cun was renamed as Li (Village). Sinshih Township was therefore renamed as Sinshih District.
