An core-Ag shell bimetallic nanoparticles, denoted as Au@Ag, have been prepared by a microwave(MW)-polyol method through the two-step reduction of AUCl(4)(-) and Ag+ ions in the presence of poly(vinylpyrrolidone) (PVP) as a capping reagent. When single crystal polygonal Au nanoplates and nanorods were used as seeds, a mixture of various Au@Ag, core-shell nanostructures was prepared after MW heating for only 2 min. Among them, small amounts of novel polygonal and rod types of Au@Ag nanostructures, in which morphologies of An core were conserved, were produced.