There are two theories on the Old Chinese vowel system: one is "one rhyme group with one vowel" and the other is "one rhyme group with multiple vowels." The rhymes of the Book of Odes are one of the most important materials for the reconstruction of ancient Chinese phonology, especially in examining the differences between these two theories. This paper aims to re-examine the one on "one rhyme group with multiple vowels" by scrutinizing the phonemes and rhymes of the earliest version of the Book of Odes inscribed on the bamboo slips preserved in Anhui University.