The invention discloses a noise lowering structure for an axial flow fan and belongs to the fluid mechanical noise lowering field. The noise lowering structure for the axial flow fan comprises a rim, fan blades, a hub and wedge-shaped structures; the rim, the fan blades, the hub and the wedge-shaped structures are integrally formed through injection molding; the fan blades start from the outer edge of the hub and sweep forwards and extend to the inner side face of the rim in the radial direction; the fan blades are distributed in the circumferential direction at equal intervals with the rotating center axis of the fan as the center; the correspondingly wedge-shaped structures are arranged on one side face of each fan blade in the radial direction; and the wedge-shaped structures comprise the two shapes of a fold line type and a curve type. According to the noise lowering structure for the axial flow fan, by means of irregular disturbance of the wedge-shaped structures on surrounding air, the pneumatic noise of the axial flow fan is lowered, and by means of the guiding effect of the wedge-shaped structures on air, the flow quantity of the axial flow fan is increased; and in addition, the noise lowering structure for the axial flow fan can meet the structural strength and fatigue life requirements of the axial flow fan in the work process and makes the overall performance of the axial flow fan improved.