Using the Zhoushan Archipelago as the study area, we investigated the status of exploitation and utilization of water resources of the islands through analysis of the characteristics and current status of the water resources. We put forward a comprehensive exploitation and utilization model called AIU(all in use), which focuses on water supply and involves flood control, drainage, water conservation, and water pollution control. Considering the fluctuation of water demands over a year, the large amount of evaporation from the water surface, and the high requirements of environmental protection on remote islands, we developed a high-efficiency water utilization system, which uses reservoirs as the storage space, intercepts catchment runoff with an intercepting trench, and collects water with shafts, in order to make the most of natural runoff.