The utility model provides a hazardous waste incineration flue gas treatment device which comprises a dust removal device, a flue gas treatment device and a flue gas treatment device, the wet deacidification device is used for removing acid gas in the flue gas through two-stage wet deacidification treatment; the flue gas-flue gas heat exchanger is arranged between the wet-process deacidification device and the dust removal device, is communicated with the wet-process deacidification device and the dust removal device through pipelines, and is used for enabling flue gas exhausted by the dust removal device to exchange heat with flue gas subjected to deacidification treatment by the wet-process deacidification device; the steam-flue gas heat exchanger communicates with the flue gas-flue gasheat exchanger through a pipeline and is used for enabling steam to exchange heat with flue gas exhausted by the flue gas-flue gas heat exchanger so as to increase the temperature of the flue gas; andthe SCR denitration device is used for denitrating the flue gas flowing in from the steam-flue gas heat exchanger so as to remove nitric oxide in the flue gas. According to the hazardous waste incineration flue gas treatment device, flue gas of the flue gas is fully utilized, energy is saved, and the purification effect is better.