The Smart Micro-Power Rain Garden is a sponge facility that integrates six major functions: infiltration, retention, storage, purification, reuse, and drainage. It overcomes the limitation of traditional rain gardens, which primarily focus on infiltration, by applying innovative concepts and perspectives to sponge city construction. The facility centers around a micro-circulation power system, with nutrient-rich substrate, shrubs, and herbaceous vegetation as the main components, supported by water-storage ecological grids. It utilizes a micro-circulation transport system as its core, guided by shallow soil sensors, water volume regulators, and air pressure balancing devices, and safeguarded by smart water management and delayed overflow facilities. This creates a self-sustaining, self-nourishing, self-purifying, and self-circulating ecological sponge system. It is designed to collect runoff from its own area and surrounding regions, reduce non-point source pollution, store reclaimed water, gradually release total runoff volume, and restore groundwater levels. Additionally, it offers water purification benefits and ecological aesthetic value as a new type of prefabricated sponge facility.