Abstract:Sponge city is a new design idea, is aimed to control and store up the partial surface runoff, and then to utilize it. Thereby, it can let a city as a sponge fully absorb or supply the water resource for the urban environment when in need. The implementation of sponge city idea can not only satisfy the demand of ecological environment benefit of urban development, but also bring the good landscape effect to the urban construction. Taking a semi-underground wastewater treatment plant WWTP in Hainan Province as an example, the design idea of sponge city is used to in the ecological design of rainwater and sewage systems in WWTP, which can reduce the influence of urban WWTP construction on the surrounding ecological environment. The sponge rainwater drainage system mainly includes the permeable pavement, gravel drain, conveying-type grassing ditch and sunken greenbelt.