The utility model discloses a lower part is the one -level absorption region in the desulfurizing tower with porous subregion sprays, tower body, and upper portion is the second grade absorption region in the tower body, is equipped with porous air flow distribution board between one -level absorption region and the second grade absorption region, porous air flow distribution board includes the plate body, and it has the weeping hole to open on the plate body, still is equipped with the ascending post of ventilating on the plate body, all is equipped with the air cap on every post of ventilating, and the tower body outside is equipped with the tower ectoplasm pond of second grade absorption region, and tower ectoplasm pond links to each other through sealed pipeline with the weeping hole. The utility model has the advantages that: the one -level sprays hangs down the operation of ph value, and the second grade sprays the operation of high ph value, reduces the energy consumption of circulating pump by a wide margin, and porous air flow distribution board is used for separating two -stage absorption system, makes the ascending flue gas and the thick liquid of decline separately pass through, has guaranteed ascending smoothness nature of flue gas and gas distribution's homogeneity, and is applicable very much to sulphur coal flue gas desulfurization, can reduce investment and running cost, and the super clean emission that is applicable to current power plant is reformed transform.