The invention provides a screw propeller capable of reducing cavitation noise. The screw propeller comprises a propeller hub, power blades, a blade fixing bolt, a charging hub, charging blades, a charging blade fixing bolt, a fairing, a propeller shaft, a charging shaft and a protective casing. The power hub is fixedly connected with the propeller shaft, the charging shaft is sleeved with the propeller shaft and the blade fixing bolt, the protective casing sleeves the propeller shaft, and one end of the protective casing is close to the power hub. The charging hub is connected with the charging shaft. The screw propeller further comprises a protective shell which is fixedly connected with the protective casing through a fixing rod and sleeves the power blades and the charging blades. As the screw propeller is of a dual-layer propeller structure, pressure between the charging propeller and the power propeller is increased, cavitation is reduced, ships can be charged by means of the charging propeller, and energy resource supplementing and ship energy consumption reduction are both achieved.