The invention relates to a device and method for glass granulation and waste heat recovery of molten smelting slag. The device comprises a chute (1), a tundish (2), a flow guide groove (3), a granulating chamber (4), a granulating fan (5), a blast groove (6), a tubular heat exchanger (8), a cooling fan (9), a spiral discharge device (10), a lifter, preferably a bucket lifter (11), a finished product bin (12), a platy heat exchanger (14), a first steam pipe (15), a second steam pipe (15), a power generator set (16) and a purifying and discharging apparatus. The molten smelting slag is convertedinto vitreous particles through the device in order to facilitate resource utilization; meanwhile, waste heat recovery is carried out, maximum recovery of molten smelting slag resources is realized,and the high-efficiency, well-equipped, automated, harmless and resourceful treatment of the molten smelting slag is achieved, and ultra-low emission is realized in the treatment process; the device has an outstanding process and the advantage of being environmentally friendly.