The invention discloses a waste incineration flue gas treatment system which comprises an incinerator, a desulfurization/dedusting integrated device, an adsorption device, a deodorization device, a sewage tank, a sedimentation tank, a sand filtering tank and an alkaline liquid tank, wherein a gas outlet of the desulfurization/dedusting integrated device of the waste incineration flue gas treatment system is connected with a gas inlet of the adsorption device, a gas inlet of the desulfurization/dedusting integrated device is communicated with an exhaust port of the incinerator through a flue, and a sewage outlet is communicated with the sewage tank; a flue gas outlet of the adsorption device is connected with a flue gas inlet of the deodorization device; and a flue gas outlet of the deodorization device is arranged below a filtering layer of the sand filtering tank through a fan and an exhaust pipe. In the invention, the spray levels of a desulfurizing tower are effectively reduced to achieve an aim of lowering the height of the desulfurizing tower; and moreover, the dedusting effect can be effectively improved.