Mengguziyun(MGZY) is an official rhyme book compiled by the Yuan court to provide an orthography for dushuyin(pronunciation for reading texts), and Zhongyuanyinyun(ZYYY) is a rhyme book for Yuanqu contains dushuyin influenced by Northern Dialect of Yuan dynasty. This study is to compare the phonological system between MGZY and ZYYY in order to investigate changes of final system in Yuan dynasty. The paper focuses on shushengyun(舒聲韻), and conclusion are as follows: Apicalization of the final [i]; dental initials of 歌 rhyme groups increased medial [u] and changed to hekou(合口, rounded group); velar initials of 陽 rhyme groups lost medial [i] and changed to hongyin(洪音); rhyme ending with [-m] of labial initials have [-n] ending.