There is still a lack of comprehensive research on the entry modes adopted by internet finance enterprises (IFEs), which are considered quintessential players in the digital economy, when expanding into foreign markets, as well as the underlying factors that influence their mode of entry decisions. On the basis of this, a theoretical model and investment environment evaluation system for the entry modes of IFEs into overseas markets have been constructed in this study, along with an analysis of the impact of investment environment on their mode of entry decisions. The cases of Ant Financial, which entry into countries along the "Belt and Road" (B&R) were used for the research. Firstly, a comprehensive evaluation was conducted on the investment environment of the countries along the B&R. Secondly, based on the theoretical model, the overseas market entry modes of Ant Financial were further refined. Finally, by using the crisp-set qualitative comparative analysis tool (csQCA), the combined effects of investment environment factors on the choice of entry location and modes were studied. The research findings indicate as follow. ① There are significant differences in the investment environment of countries along the B&R. ② The main entry modes of IFEs can be classified into four types based on the degree of control and resource commitment, including investment with technology and experience output, equity investment, strategic cooperation, and access to services; ③ IFEs tend to enter neighboring countries of their home country, as well as regions with more market demand and better infrastructure. Countries with higher levels of government governance but poor institutional environments are not suitable for high-control and high-resource commitment entry modes. When the institutional environment is poor, strategic cooperation can be used to enter, thereby avoiding political risk. This study is of certain significance for the theoretical and practical development of internationalization of IFEs in the context of the digital economy.