Abstract: Disclosed are an apparatus and a method for granulation of a blast furnace slag and recycling of waste heat. The apparatus comprises an aerosol granulation nozzle module, a flow guide, a cyclone separator and a waste heat recovery device; wherein the aerosol granulation nozzle module comprises a slag flow controller, a compressed air flow control valve, a water volume control valve and an aerosol spray gun; the flow guide is configured to fully mix the medium temperature gas and the high-temperature granular slag having a primarily solidified surface in the flow guide; and the cyclone separator is configured to separate the high-temperature granular slag and the medium-to-high-temperature gas. The present invention completes the granulation of blast furnace slag, and organically couples slag sensible heat recovery with sludge drying, thereby recovering the waste heat in the process of slag granulation and improving the efficiency of waste heat recovery and utilization.