Due to the long history of construction and poor maintenance of the old community in the high-density built-up area, there are many problems in the drainage system, which have a serious impact on the operation of the urban sewage treatment plant and the urban water environment. Therefore, effective control of the sewage discharge in the old community is the most important link in the work of improving the quality and efficiency of sewage. Taking a old community in Xiamen as a specific research case, and analyzing its current drainage situation, taking into account the urban renewal planning and technical, economic and other factors, the paper studies the technical route and implementation strategy for improving the quality and efficiency of the sewage system in the old residential district under the urban renewal scenario, which can serve as a reference for subsequent reconstruction.