The invention discloses a wet desulphurization mechanism. The wet desulphurization mechanism comprises an original smoke deflector and a smoke heat exchanger, wherein an original smoke opening is formed in the smoke heat exchanger, the cross section of the original smoke opening is rectangular, the original smoke deflector comprises a first elbow and a second elbow, the cross sections of the first elbow and the second elbow are round, and both the first elbow and the second elbow are mounted on the original smoke opening of the smoke heat exchanger. As the first elbow and the second elbow, of which the cross sections are round, are arranged at the original smoke opening of the smoke heat exchanger, smoke can be shunt by the first elbow and the second elbow before entering the smoke heat exchanger, and sufficient bending spaces are available at the first elbow and the second elbow. Besides, the first elbow and the second elbow have smaller round cross sections and great deflecting functions, the whole flow field becomes more uniform, the heat exchange efficiency of the smoke heat exchanger is effectively improved, and the risks that the easily torn deflector plate designed in the traditional rectangular runner causes corroded cracks, corroded flues, runner blocking shutdown and the like are eliminated.