Abstract: Noble-metal nanoparticles have attracted tremendous interest on account of their merits in optics and catalysis. Their properties are strongly dependent on size, shape and composition. However, it is still a great challenge to control the growth process of metal nanocrystals to achieve a desired shape. In this paper, we decribe the use of single crystalline Au nanorods (NRs) with fixed facets and unique optical properties as seeds to prepare various core-shell hybrid nanostructures, including Au@Pd nanobars, arrow-headed Au NRs, Au nanooctahedra, orange segment-like Au@Ag nanoparticles, Au@Pt island NRs, and Au@PtAg island alloy NRs. The optical and catalytic properties of hybrid nanostructures are regulated via the composition and structure. Our investigations indicate that the formation of hybrid nanostructures is an effective way to tailor the properties of nanomaterials.