The subject of this study is Japanese research on Yùnjìng by Japanese scholars. This study carried out from the perspective of philology and Chinese phonology. This research found out two major roles of Yīnyùnrìyuèdēng in Chinese phonology in Japan. First, Yīnyùnrìyuèdēng is one of the most important references related to Chinese phonology during 17-18th centuries. After the spread of Yīnyùnrìyuèdēng, it mentioned Yīnyùnrìyuèdēng many times in in Japanese research on Yùnjìng. Sometimes it used for the reference about Chinese phonological terms. Second, Yīnyùnrìyuèdēng has a role of distinguishing a genealogy.