The invention relates to a centrifugal fan noise reduction blade structure. The centrifugal fan noise reduction blade structure comprises a blade, wherein a plurality of first cavity grooves are formed in the windward surface of the blade at intervals; a plurality of second cavity grooves are formed in the tail of the blade; the cross section area of the second cavity grooves is greater than the cross section area of the first cavity grooves; and preferably, the cross section of the second cavity grooves is rectangular. The first cavity grooves which are formed in the surface of the blade are used for decreasing the separation of the boundary layer on the surface of the blade; the second cavity grooves which are formed in the tail of the blade are used for decreasing the periodic falling of eddy on the tail edge of an impeller; the first cavity grooves and the second cavity grooves act synergistically; and most of the transverse flow in the cavity grooves is obstructed by the boundaries of the grooves, large-scale vortex cannot be formed, and the retardation increases the effective thickness of the viscous sublayers and decreases the speed gradient on the wall surfaces, so that the production of noise is greatly reduced. In a preferably scheme, impact loss is generated when gas flows through the rectangular grooves, so that the pressure of the gas in the boundary layer of the blade is before the separation effectively decreased and the noise effect is better.