The invention provides a desulfurization and dedusting integrated system. The desulfurization and dedusting integrated system comprises a desulfurization tower, the bottom of the desulfurization tower is provided with a flue gas inlet, the desulfurization tower is internally provided with a spraying layer, a flue gas flow rectifier is arranged between the flue gas inlet and the spraying layer, the top of the desulfurization tower is provided with a flue gas outlet, a wet electrostatic precipitator is arranged at the flue gas outlet, and a flue gas rectification grille and a flue gas guide plate are arranged sequentially between the wet electrostatic precipitator and the flue gas outlet. A plurality of atomizing nozzles are arranged on the spraying layer, and each atomizing nozzle is a one-direction double-head structured nozzle and comprises a nozzle body and two spraying holes symmetrically and relatively obliquely formed in the nozzle body. A clearing mechanism is arranged between the flue gas rectification grille and the flue gas guide plate, and accordingly liquid drop scaling, flue blockage and corrosion of two reactors can be avoided effectively, system resistance is greatly reduced, and scales on the flue gas rectification grille and the flue gas guide plate can be cleared timely.