This paper has an investigation on the rhymes of the four dramas by the dramatist Ruan DaCheng, a well-known "traitor","betrayer" in the late Ming Dynasty. We find that the rhymes of the four dramas are not in accordance with "ZhongYuan YinYun" , which differ a lot from what Che WenMing（2001）said about Ruan`s rhymes. Ruan`s rhymes has his own characteristics. For example, the words in "Geng Qing" "Zhen Wen" and "Qin Xun" rhyme with one another, So do the words in "Han Shan" "Huan Huan" "Xian Tian` ``Jian Xian" and "Lian Xian", "Zhi Si", "Qi Wei" and "Yu Mu", "Che Zhe" and "Jia Ma", and so on. In addition to the tradition of NanXi, the rhymes also has a certain relationship with Ruan`s dialect and the Suzhou Dialect. However, the rhyme modes of the entering tone words are different from that of NanXi. The entering tone words rhyme with the words with vowel finals, which probably reflects some features of Beijing dialect at that time.