Monodispersed nickel spheres with diameters ranging from 100 nm to 180 nm were prepared by microwave-assisted(MW)polyol method.The magnetic stripe domain structure in these nickel spheres was measured by magnetic force microscopy(MFM).Furthermore,in this work we reported the formation of core-shell structures of highly globular NicoreNiOshell which were synthesized from the Ni spheres,and the magnetic properties of the core-shell structures have been investigated.