This study analyzed the [ə]-rhymed words in the spontaneous speech of 8 speakers in the Tainan dialect of Taiwan Southern Min. The results indicated that among the 42 observed [ə]-rhymed words, [ə]/[(The Symbol is abbreviated)] free variation was practiced on 19 words, indicating the ongoing collapse of the phonemic contrast between these two vowels in Tainan dialect. In addition, statistical analysis displayed significant correlation between the [ə]/[(The Symbol is abbreviated)] free variation and word frequency. Words of high frequency tends to perform [ə]/[(The Symbol is abbreviated)] free variation.