The utility model discloses a device for inhibiting PCDD/F (Polychlorinated dibenzopdioxins/dibenzofuran) in incinerating gases. The device comprises a waste heat boiler (1), a spraying and fluidifying quench tower (2) and an induced draft fan (3), the operation unit equipment is connected in sequence. A method adopting the device to inhibit PCDD/F in the incinerating gases comprises the following three courses: temperature reduction of flue gases at the high-temperature segment in a controllable manner, spraying and fluidifying quenching at the moderate-temperature segment and dust removal and absorption at the low-temperature segment. Within the safe-temperature interval range not generating PCDD/F, at first, high-temperature flue gases from an incinerator is reduced to the moderate-temperature segment by adopting a waste heat recovery method, and then quenching temperature reduction is implemented within the sensitive temperature region generating PCDD/F, so that the content of PCDD/F in the exhausted incinerating gases is greatly lower than the control index specified by the national standard. The device and the method adopted by the device, provided by the utility model, have the characteristics of controllable quenching time and temperature, excellent quenching effect, no solid waste and waste water and the like, and are suitable for purifying various waste incinerating gases so as to achieve emission reduction of PCDD/F.