We report the formation of a new type of nanosized composite of copper silicide nanocrystals embedded in a silicon nanowire that obtained by laser ablation of Si/metal mixture targets at 1200 degreesC in an argon gas flow. Like the bulk phase of crystal silicon, the copper atoms were found have a high solubility in the silicon nanowires and precipitate in the nanowires, The silicon wires are smooth in surfaces and straight in length, while the copper silicide nanocrystals are sphere-shaped. The diameters of the nanocrystals increase with that of the host nanowire, Because of Si nanowires and copper silicide nanocrystals have distinctive electronic and optical properties, the composite nanowires may possess unique properties arising from both the size and the interface effects that are of fundamental and application interests.