《博雅音》是一部反映公元6世纪末至7世纪初南方书音系统的重要文献。它的唇音是否有轻重的区别对研究汉语唇音及轻唇化年代问题有着十分重要的参考意义。鉴于此,我们对其唇音音切进行了穷尽性的整理和比较,得出它的分布类型与《切韵》的一致性:即重唇多切一二四等韵,轻唇多切三等韵;重唇切轻唇较少,轻唇切重唇较多①,且基本见于三等韵。《博雅音》与《切韵》一样并未发生轻重唇的分化,轻唇音不能看作是独立的音位。表明至迟在公元7世纪前叶,在南方书音系统中轻唇音尚未独立成类。 “Burson-Marsteller” is an important document reflecting the Southern Call System from the end of the 6th century to the beginning of the 7th century. Whether or not there is a difference between its lip sounds is of great significance to the study of the problems of Chinese lip sound and light lip lip age. In view of this, we conducted an exhaustive sorting and comparisons of lip lip sound cuts, and concluded that its distribution type is consistent with the “cut rhyme” Rhyme; heavy lip cut less lip, lips lip heavy lip more ①, and the basic found in the third rhyme. “Burson-Marsteller” and “cut rhyme” did not occur the differentiation of light and heavy lips, light lip sound can not be regarded as an independent phonemic. It shows that the light lip sounds have not been independently classified in the southern pronunciation system till the late seventh century AD.