The invention provides a slag granulating and waste heat recovery device, comprising a slag pot, a slag ladle, a granulating device, a primary cooling fan, a discharge device, a secondary cooling fan, a heat exchange shaft furnace, a cyclone dust collector, a waste heat boiler, a dust collector and a chimney, wherein the slag pot is used for containing slag; a water port is arranged at the lower part of the slag ladle; the granulating device is used for granulating the slag in the slag ladle; the primary cooling fan is used for providing primary cooling air; the discharge device is used for discharging granulated slag; the secondary cooling fan is used for providing secondary cooling air; the heat exchange shaft furnace is used for performing heat exchange between the granulated slag discharged by the discharge device and the secondary cooling air; the cyclone dust collector is used for removing fine particle slag from the primary cooling air and the secondary cooling air; the waste heat boiler is used for generating high-temperature stream; the dust collector is used for collecting dust in the tail gas generated by the waste heat boiler; and the chimney is used for discharging the tail gas after dust collection. By using the slag granulating and waste heat recovery device according to the invention, no new water is consumed in the slag granulating process, the slag waste heatcan be effectively recovered for power generation, and the slag vitreous body after treatment can be used as a construction raw material.