Abstract: In modern researches of old Chinese phonology, the exploration and reconstruction of ancient Chinese vowels and medials are mainly based on materials for medieval times, including phonetics, dialects, foreign transliteration and Fanqie, and then trace back to the earlier time. The Book of Songs has been only used to study rhyme categories (Yunbu) of old Chinese, other than vowels and medials. However, rhymes in The Book of Songs, which pursue the harmony of vowels and medials, can also reflect the nature of them. This paper builds a database to analyze rhymes of The Book of Songs. There are altogether 4540 must-rhymed sentences in 1695 rhymed sections. The rhymed characters can be divided into seven groups according to Four Division (classification of finals in Chinese phonology). By comparing similarities and differences between groups reflected by the co-occurrence frequency of them in the same rhymed sections, we can know the distribution of main vowels, the classification of medials and their relations of old Chinese rhyme categories.

Key words: The Book of Songs, old Chinese phonology, Four Division, ancient Chinese dialect, Chongniu, vowels, medials