Abstract: There are many cross-border rivers in China. In order to ensure the water quality of cross-border sections to meet the standards, it is necessary to strengthen the prevention of water environmental pollution risk of cross-border rivers. The solutions to the construction of the environmental emergency interception facilities for the cross-border rivers were put forward, and the design ideas and principles discussed. It was proposed that the environmental emergency sewage interception facilities should include emergency interception dams and supporting sewage receiving wetlands, and the requirements for the design of the facilities were elaborated from the aspects of dam design, wetland design, emergency measures design, minimal environmental impact and operating conditions. Taking a cross-border river in the northwest of China as an example, the case design of environmental emergency sewage interception facilities was carried out. Based on the analysis of the characteristics of the river and the risk sources of the water environment, the design was carried out from the aspects of project location comparison, the selection of the dam type, the dam height and the main design parameters of the constructed wetland, and the treatment efficiency of the environmental emergency sewage interception facility was simulated. The results showed that the construction of environmental emergency sewage interception facilities would greatly improve the environmental risk prevention ability of the river, and the facilities could play the role of drainage and restoration of other wetlands along the coast when no water pollution accident occurred.