The “Belt and Road (B&R) Initiative” is an innovative idea proposed by China aimed at promoting common prosperity in the world. Although it has gained more and more recognition and response, there is also some one-sided understanding or distortion. Taking the 60 countries along the Belt and Road from 2010 to 2015 as samples, this paper mainly answers three questions from the perspective of sustainable development: (1) What is the current status of sustainable development in all countries along the “B&R”? (2) Is the “B&R Initiative” conducive to promoting the sustainable development of all countries along the “B&R”? (3) How could the “B&R” be better promoted? The study found that, first, various countries along the “B&R” have manifested an imbalanced characteristic in terms of the sustainable development, and there is much room for improvement in general. Second, the “B&R Initiative” has a positive impact on the sustainable development of all countries. However, due to the relatively short period of time, this impact is not significant at present. Third, to promote “B&R” construction, we must take sustainable development as the fundamental goal to jointly promote the connectivity of facilities, integrate the UN 2030 sustainable development goals, and strengthen the cross-border cooperation between non-governmental and non-profit organizations.