Countries along the "Belt and Road" have huge market demand and development potential, and improving their investment facilitation level is of great significance for China to expand the scale and quality of direct investment to countries along the route. Based on the characteristics of countries along the route, 4 primary indicators of infrastructure, institutional environment, financial market, labor market and 20 secondary indicators are selected to construct a set of investment facilitation level measurement system, using entropy method to measure the investment facilitation level of countries along the "Belt and Road" from 2014 to 2018, the results show that there is a big difference in the investment facilitation level of countries along the route but the overall trend is increasing year by year, and the regional imbalance is prominent, and the investment facilitation level is positively correlated with economic development. On this basis, combined with the current challenges faced by China in direct investment in countries along the route, it is suggested that China and the countries along the route should strengthen cooperation, jointly promote infrastructure construction, maintain a transparent and efficient institutional environment, deepen bilateral financial cooperation, and actively develop domestic labor market.