Using data on Chinese enterprises’OFDI, this paper decomposes the total investment into the intensive margin and the expansion margin, then explains the growth path of Chinese enterprises’investment in BRI countries. The results show that both the intensive margin and the expansion margin are the paths for the Belt and Road Initiative to promote the growth of the total OFDI. In terms of investment method, the intensive margin in cross-border M&As is stronger than greenfield investment, while the expansion margin is weaker than greenfield investment. In terms of investment direction, the binary margin has a significant positive effect in forward investment, but the opposite effect for countries in reverse investment. In terms of industry category, the binary margin in the transport and energy sectors is better. The mechanism test suggests that improving the stability of Chinese enterprises’OFDI should further enhance the marginal contribution through the Belt and Road Initiative’s connectivity building.