This chapter examines decision-making mechanisms among Global South countries from a political-institutional perspective, focusing on how institutional design can enhance collective decision-making efficiency. The chapter begins by comparing the institutional strengths and weaknesses of major voting systems, and summarizes the historical evolution of unanimity voting, majority voting, and weighted voting systems. After summarizing the above-mentioned voting system, we mainly analyze the advantages and disadvantages of the consensus voting system. It further proposes institutional adjustments to mitigate the structural limitations of consensus-based mechanisms, thereby enhancing their flexibility, adaptability, and procedural efficiency of the consensus voting system from different levels. These characteristics can also have a positive effect on the formation of decisions by countries of the Global South. On this basis, the countries of the Global South can continue iterative negotiations and institutional coordination, reach consensus on key issues, deepen mutual understanding and understanding, and contribute to the establishment of a trust mechanism, finally, an effective resolution of regional international law will be formed, in solving the problems brought about by globalization, deepening the cooperation and exchanges between the forces of the “Global South”, and establishing a long-term mutual consultation and trust mechanism through the concept of “A community of shared future for mankind”, the “Consensus” voting method will play its important value function and advantages.