Disclosed is a dust and mist removal device for wet desulfurization. The dust and mist removal device for wet desulfurization comprises a multi-stage mechanical dust and mist removal device and a wet electrostatic precipitator; wherein the multi-stage mechanical dust and mist removal device is connected in series to the wet electrostatic precipitator to form an electromechanical wet dust and mist removal unit, the multi-stage mechanical dust and mist removal device is positioned at a lower part the wet electrostatic precipitator, the multi-stage mechanical dust and mist removal device matches with the wet electrostatic precipitator in terms of cross-section shape and size, and the number of electromechanical wet dust and mist removal units arranged in parallel is defined according to a flue gas amount to be treated. According to the present application, the dust and mist removal efficiency is improved, the use is convenient and the cost is low.