Abstract:The assimilation of entering tones into falling tones is one of the core characteristics of the Neijiang dialect, particularly in the Renfu sub-dialect which is a branch of Sichuan (Southwest) dialect. The poetry and prose by ZHAO Zhenji and Zhangxue (a Zen master) who are both Neijiang native literati in the late Ming Dynasty They frequently feature rhymes that include a significant number of zi(Chinese characters) with entering tones and falling tones. This reflects the close relationship between these tones in the Neijiang dialect during the late Ming dynasty. It can be concluded that the assimilation of entering tones into falling tones can be traced back to this historical context.