The invention relates to an autocatalytic denitrification process of sintering smoke dust by coupling utilization of smoke dust waste heat. According to the technical scheme, sintering smoke dust penetrates a sintering material layer, a bottom layer, a bottom grate of a sintering machine trolley and bellows under the trolley and enters a main flue under the draft action of a high-pressure blower; a sintering machine is divided into an ignition section, a machine head section, a smoke rapid heating section and a machine tail section in the traveling direction of the sintering machine trolley sequentially, the sintering smoke dust flows out of a main flue, passes through a denitrification smoke heat exchanger and a smoke heater sequentially and enters a fluidized bed denitrification reactor; liquid ammonia is sprayed into the bellows under the machine tail section, the bellows under the smoke rapid heating section and a smoke outlet pipe of the smoke heater, so that the sintering smoke dust is subjected to a denitrification reduction reaction with ammonia gas under the catalysis effect of particles which are rich in iron oxide and carried by the sintering smoke dust. The process has the advantages of simple process, no purchased catalyst, high recovery of waste heat, small floor area, low equipment investment and low operation cost, is energy saving and reduces consumption.