Abstract: Water right trading institutional system is an important approach to efficiently allocating water resources under the condition of market economy, as well as a key means to promote use efficiency and conservation of water resources. Based on water rights trading practices across the Changjiang River Basin, this study examines the existing challenges in water rights transactions within the region by considering its unique water resource endowment characteristics and practical demands. We propose five key institutional system improvements: ① Accelerating the establishment of an initial water rights allocation system; ② Enhancing the water resource monitoring system; ③ Developing a comprehensive water rights trading market framework; ④ Constructing an integrated water rights trading platform; ⑤ Strengthening the regulatory and oversight mechanisms for water rights transactions. These systemic measures aim to standardize and advance water rights trading practices in the water-rich southern regions of China, thereby providing a robust institutional guarantee for achieving Pareto optimality in water resource allocation efficiency and utilization effectiveness throughout the Changjiang River Basin.