Shanshang is an alluvial plain created by the frequent flooding and silt build up of the Zengwun River. Hence, neighboring villages were once named as Nanshihjhou (modern day Nanjhou Village) and Beishijhou. The region was first populated by soldiers led by Yu Shih-lung, a general under Jheng Cheng-gong. The soldiers cleared the land to make way for farms that helped to sustain their garrison. The population grew over the years and new villages were founded. Originally, Shanshang region was one of the settlements of the Siraya tribe of the Pingpu people. As the settlement was located atop a fluvial terrace, people looking up from a lower elevation would regard the settlement as being located on a mountaintop. This gave rise to the name of Shanzaiding (top of the mountain). When the Japanese occupied Taiwan, Shanzaiding was used to name the region. Owing to the regional merge and reorganization of Tainan city and county on 1 October, 1920, the name subsequently changed to Shanshangjhuang.
Reorganization of Taiwanese administrative districts in 1920 formally renamed the Shanshang area as Shanshangjhuang, which was administered by Sinhua Ken of Tainan-Shu.
After the Retrocession of Taiwan, Tainan County Government was established on 7 January, 1946 where Gai (streets) were converted into Jhen (towns), and Sho were converted to Siang (villages). The local Township Office was established on 18 January 1946, retaining Shanshang as the region's name. In 1 July 1946, the two villages of Neitanding and Dashe were reorganized to form Sinshih Village, while Pinghe Village of Zuojhen Township was relegated to Shanshang Township and renamed as Pingyang Village.
In 25 December, 2010, Tainan City and County were merged to form a municipality. The area was reorganised as Shanshang District.