The invention relates to an integrated flue gas desulfurization and dust removal device used in a coal-fired power plant. A flow equalizing and effect improving plate is arranged above the inlet of an absorption tower, 2-5 spraying layers are arranged in the range of 1.5-3 m above the flow equalizing and effect improving plate, the separation distances of the spraying layers are 1.8-2.5 m, 1-2 layers of effect improving rings are arranged in the middles of the spraying layers, and a pipe precipitator is arranged above the upmost spraying layer. The integrated flue gas desulfurization and dust removal device has the advantages that the air-liquid contact time is increased by the flow equalizing and effect improving plate, more dissolution choices are provided in an absorption region, and accordingly the sulfur removal efficiency is improved; air-liquid distribution can be evener, the phenomenon that regions different in liquid-air ratio are different in desulfurization and dust removal efficiency is avoided, and accordingly the integrated flue gas desulfurization and dust removal efficiency of the device is improved. The liquid-air ratio of the desulfurization device is reduced, the spraying slurry amount is saved, the number of the spraying layer is decreased, wet-type electric precipitators and other large dust removal devices are not additionally added, the transformation work amount and operation costs are greatly reduced, and a transformation work period is shortened.