In order to study the port investment risk of countries along "the Belt and Road", this paper selects the panel data from 2010 to 2019 to build an index system from the five dimensions of political risk, economic risk, social risk, relations with China, and the development of the port industry, and evaluates the port investment risk based on the dynamic factor model. The results show that: From the country perspective, the country with the lowest investment risk is the Netherlands, and the highest is Nigeria. From the region perspective, the port investment risk in Europe is the lowest and that in Africa is the highest. From the time perspective, the port investment risk for most countries along the line shows a decreasing or stable trend, but the opposite is true for Australia and some countries in Western Asia. When Chinese enterprises invest in overseas ports in the future, they should reasonably select the investment area according to the risk level, and be alert to the threats and challenges brought by the epidemic to Chinese enterprises.