How to establish a credit system for the trading of water rights is studied based on the characteristics of market of water rights in China. A total of 12 typical cases of trading of water rights in the northern and southern regions are selected, and the QCA method, a qualitative comparative analysis method, is used to extract the key factors affecting the credit system of the market of water rights from the technical, institutional and cultural levels. Some countermeasures are proposed in terms of improving the monitoring technology, promoting the information disclosure system, clarifying the evaluation criteria, increasing the rewards and penalties, and strengthening the work of cultural propaganda.