The utility model relates to treatment equipment of industrial waste gas, and in particular to flue gas desulfurization treatment equipment. The equipment comprises a thickening tank, a buffer tank and a packed tower, wherein the thickening tank is communicated with the packed tower through the buffer tank; a wastewater inlet and a waste residue outlet are arranged on the thickening tank; and a buffer solution inlet, a waste liquor outlet, a tail gas outlet and a flue gas inlet are arranged on the packed tower. The equipment disclosed by the utility model has the advantages that sulfur dioxide flue gas is absorbed by using industrial alkali wastewater, so that the use ratio of industrial wastes is greatly increased; and replenisher is added at the same time to replenish the packed tower, so that the desulfurization operation can be continuously carried out. The equipment is particularly suitable for popularization and application in the industries of smelting, chemical engineering, electricity and the like.