In the new phase of high-quality Belt and Road cooperation, China needs to enhance the cost-effectiveness of the Belt and Road Initiative (BRI) and improve its resource utilization efficiency and concentration. This requires a foundation that focuses on key areas while maintaining a holistic perspective. The approach entails following a cooperative path characterized by unidirectional propulsion, bidirectional interaction, and multidirectional synergy, ultimately achieving these goals through the method of linking points into corridors and extending corridors into networks. As a novel, development-oriented regional cooperation mechanism, the BRI features functional cooperation centered on development, which aligns closely with the precise positioning of middle powers pursuing a “niche strategy” through a functionalist approach. Moreover, the BRI’s open regionalism resonates strongly with the mechanistic and structural role that middle powers seek in fostering cross-regional cooperation across broad geographic areas. Therefore, from the dual dimensions of motivations and orientations, this paper concludes that middle powers can serve as pivotal actors in advancing the high-quality development of the BRI. It proposes specific and feasible measures: leveraging middle powers as strategic pivots to engage in “third-party market” cooperation, strengthening targeted research, and enhancing people-to-people exchanges, to improve the efficiency of BRI cooperation.