The cross-border circulation of RMB is an important vehicle for Chinese multinational enterprises’OFDI, and the influence mechanism of its circulation level on investment efficiency is worth studying. The results of the benchmark regression in this paper show that the cross-border circulation of RMB can promote the efficiency of China’s OFDI to the countries along the Belt and Road Initiative. Further study shows that RMB cross-border circulation has a significant positive effect on China’s OFDI efficiency after the Belt and Road initiative was put forward, and it has a significant positive effect on China’s OFDI efficiency in“One Belt”countries, high institutional quality countries and high economic development level countries. The exchange rate transmission mechanism of the impact of RMB cross-border circulation on China’s OFDI efficiency is established, showing a negative weakening effect. China should strengthen cooperation with countries along the route in the construction of financial services infrastructure, promote investment and financing facilitation, and strengthen institutional cooperation to improve investment efficiency.