This paper points out some theoretical problems of Eom`s (2012) Chuggugo umunnon gwa ungyong, Mandarin phonology and its application. The problems include (1) the unclear status of vocalic coda in syllabic structure, (2) the improper rule ordering of vowel changes and (3) the illogical mechanism of retroflexion or R-suffixation. This paper proposes to revise them as follows: a. The post-nucleus glide should be placed at the coda position not in approximants as j and w, but in vowel symbols as i and u. b. Those rules concerning the vowel assimilation are proposed to be presented in the order of onset, nucleus, and coda unless they are crucially ordered. The rules applicable to the wider range precide the opposite ones. c. Those rules concerning retroflexion are proposed to be presented in the order of superimposition of retroflexion, schwa insertion, and front sound deletion. The revised theories will be adopted in the second edition of Eom`s book, which will appear in 2016.