『Xiziqiji』is a text written by Mateo Ricci and published 1605 and it contains romanized pronunciations of Chinese characters. These romanized descriptions of Chinese pronunciations are considered to include information on Chinese phonological system in Ming Dynasty Era. This paper analyzed these romanized pronunciations in an effort to explore Chinese initial system in late Ming Dynasty period. First, 『Xiziqiji』shows devocalization of voiced sounds, aspiration, merge of 非-initial, some of the 微母 characters becoming zero initial, some of the 疑-initial characters becoming zero initial, merge of 知 group and 章 group, merge of 莊 group and 精 group, changes of er syllable.