Abstract: To combine urban rainfall resource utilization with greenfield system planning and lay theoretical foundation for the construction of regional water-saving greenfield that aims at saving urban fresh water resources, we select Haxi District of Harbin as the subject and study the potential of local rainfall resources. The zones able to collect rainfall were identified as water-saving greenfield by using surface-water hydrological analysis technology of GIS, based on which the greenfield system of the district was planned and designed. The status quo of rainfall resources utilization in China, the characteristics of the study area, and the planning, structure and layout of its water-saving greenfield system are introduced.