The invention, which belongs to the field of flue gas desulfurization technique, provides an integrated coupling device for flue gas desulfurization and dedusting, which includes: a tower body, a tangential intake port, a flue gas exit port, a bottom layer rotational flow board, a inward sprinkler plate, a spraying layer, a lower defogging board and a upper defroster, wherein a central overflow tube is located in the center of the inward sprinkler plate, several injection blades are fixed and equipped on the outer edge of the central overflow tube angularly from layer to layer in a regular polygon mode, and the support plate tendon is connected with double ends of every piece of injection blade in a fixed connection. The invention uses the inward sprinkler plate in an unique design, and couples the spraying method and the rotational flow method in an organic combination, the inward sprinkler plate has multiple efficacies of desulphurization, dedusting, air flow distribution improvement as well as doctor solution influx, thereby the device provided by the invention has high-efficient desulphurization and dedusting functions, moreover reduces the liquid-gas ratio and airflow resistance obviously.