In view of the current situation of water resources scarcity and comparatively low recycling utilization of living waste water, an intelligent water-saving system is designed for selectively recycling high-quality waste water. Through analyzing the work condition, this research introduced the operation theory of the system, designed the key parts (water-collecting valve, filtering and noise-reducing barrel), the hardware and software of control system, briefly expounded principles and methods of turbidity testing, and used real model to have a comparative analysis of the system. The result shows that this water-saving system runs stably and makes the reduction rate increased by about 31% , therefore it has a good application and dissemination.