The aim of this study is to explore what factors influence RMB internationalization in the process of the Belt and Road. It firstly makes a summary of the important influencing factors, then sets up a semi-logarithmic model to quantitatively analyze these factors, and finally puts forward suggestions for the steady development of RMB internationalization. Through literature review, it is found that since the Belt and Road initiative was put forward, RMB has been used more extensively in the surrounding countries and regions. Through quantitative research, it is found that with China's GDP as a share of world GDP, the scale of imports and exports of goods and services, and economic freedom are all positively related to the internationalization of RMB; the inflation rate and the volatility of real effective exchange rate are negatively related to it. This paper suggests that China should vigorously develop the national economy, expand the trade scale and maintain the stability of the RMB currency value. Meanwhile, it should also improve the market mechanism and increase economic freedom under the guidance of the central government. The marginal contribution of this study is to add to the econometric model an explanatory variable of economic freedom representing the impact of the Belt and Road initiative.