Si/Pd nanostructure was obtained by preparing Pd nanoparticles on the surface of SiNWs, and employed as catalyst in the degradation of eosin Y in the presence of sodium borohydride, which demonstrated high catalytic activity and could be reused. The reaction rate of eosin Y degradation with Si/Pd nanostructure catalyst enhanced ca. 24 times compared with unsupported Pd and ca. 4 times compared with polymer-supported Pd within eosin Y concentration from 5.0×10 −5 M to 4.5×10 −5 M. The Si/Pd nanostructure still showed high catalytic activity after five times recycle during the whole degradation.