Abstract: To explore the improvement method of river water quality in the highly urban built-up area, the Tiepai River in Baoan District, Shenzhen City is selected as the study area. Based on the characteristics of different reaches, the ecological water demand of different reaches, the minimum ecological discharge of the reservoir and the potential resources of reclaimed water and rainwater, the ecological compensation resolution is proposed. The research shows that under the premise of the minimum discharge released by Tiegang Reservoir, the rainfall of each reach of Tiepai River can not meet the ecological environment water demand, which can only be used as intermittent compensation. The reclaimed water of the Gushu sewage treatment plant can be used as a normal water source. After artificial storage, physical and chemical treatment, the rainwater can be used to replenish rivers in urban built-up area, and ecological storage and regulation methods can be used to purify the rainwater at river reaches with large space, so as to reduce the pollution concentration. The construction of ecological gravel beds, ecological floating islands and underwater forests can improve the water ecosystem and ensure the stability of ecological functions.