This township was originally Longjiaotan bao of Chiayi Prefecture. In the past, as there were many different kinds of bamboos (jhu) growing here, it was called as “Tou Jhu Wei” and “Er Jhu Wei”. As the word “er” is pronounced the same as word “yi”, it is called likewise. It was also said that when the Japanese army invaded Taiwan, Prince Kitashirakawa Yoshihisa subdued Yijhu from Bajhang River. When he passed by the Lintou Lane, Renli Village of Yijhu Township, a warrior hidden in a tree stabbed the prince dead with a scissors knife. Infuriated, the Japanese army burnt the entire village. It was quite a calamity then. Later, there were forty-nine martyrs scarified. In order to commemorate their righteous acts (yi), the township was named “Yijhu Township”.
On October 1, 1920, Yijhu Village was affiliated with the Dongshih Village Office, Tainan Prefecture, located at 529 Banchi. On August 21, 1929, it was moved to its current address. On October 25, 1945, rule over Taiwan was returned to the Republic of China. In January, 1946, it was affiliated to Tainan County. On January 18 of the same year, it was renamed as Yijhu Township Office. On October 25, 1950, provincial administrative district was adjusted, and local self-government was established, with the implementation of the county system. Then, Yijhu Township became affiliated with Chiayi County.