Pt-decorated nanostructured silicon nanowires (SiNWs) are incorporated into the counter electrode (CE) of dye sensitized solar cells (DSSCs). The Pt particles are introduced to the SiNWs uniformly by electroplating method and compared to a CE fabricated with sputtered Pt, the catalytic activity and charge transfer rate are improved notably. 0.5% of electroplated Pt on the SiNWs electrode introduces an electrochemical active higher than that offered by sputtered Pt CE. The resulting energy-conversion efficiency (η) is ∼8.30% (under an illumination of AM 1.5G, 100mWcm−2) which is better than 7.67% achieved from a similar device comprising a sputtered Pt CE. This results indicate that the composite film with high conductivity, large active surface area, and good catalytic properties for I3− reduction has large potential as the counter electrode in a high-performance DSSC thereby rendering silicon catalyst-based monolithic DSSC commercially practical.