Silver-silica composite particles with a core-shell structure were been obtained. The thickness of the silver nanoshell could be easily tailored by varying the number of deposition cycles. The method for fabricating such particles was based on a seed-mediated growth technique, where metal silver nanoparticles tethered on a silica sphere served as nucleation sites for the growth of a silver nanoshell overlayer. The approach using seeds of the same materials as the shell metal could avoid effects caused by additional metals. Such seeding enlargement of the tethered nanoparticles helped to plant a complete and a more close-packed silver shell layer. The optical properties of core-shell particles had been investigated. By changing the thickness of the silver nanoshell, the optical properties could be tailored as expected.