As the local government of Zhuhai has always attached importance to the water environment improvement of flood drainage canals (river branches), sewage interception and regulation projects in various districts have been carried out. Although sewage was collected by means of sewage separation, centralized interception, branch interception and partial drainage transformation, the effect of sewage interception was not satisfactory.After field investigation of various sewage interception practices implemented, it is found that the sewage separation canal has remarkable effect on the regulation of black and odorous water in east Nanping flood drainage canal, which can fully realize the goal of collecting and treating all these wage from confluence system area in sunny days and effectively controlling overflow pollution in rainy days, as well as avoiding waterlogging at the same time. By controlling pollution sources, combined with microbial remediation, ecological simulation, nano-aeration, water quality improvement and other means, the ecological remediation of river water was carried out, and the purification of river water was basically realized.