Wireless　power　transfer　(WPT)　received　widespread　research　in　various　field,　such　as　wireless　power　in　consumer　electronics　and　electric　vehicles.　Recent　researches　have　shown　that　adding　metamaterials　to　the　WPT　system　was　an　effective　method　to　enhance　transmission　efficiency　and　distance.　In　view　of　the　fact　that　traditional　metamaterial　slab　often　had　a　single　working　frequency　point　and　was　not　suitable　for　multifrequency　WPT,　this　letter　analyzed　and　discussed　the　mechanism　of　magnetic　negative　metamaterial　enhancing　WPT　efficiency.　Moreover,　two　kinds　of　metamaterials,　self-resonant　dual-band　negative　permeability　(SRDB-NPM)　metamaterial　and　externally　compensated　dual-band　negative　permeability　(ECDB-NPM)　metamaterial,　were　designed.　Finally,　the　effectiveness　of　two　kinds　of　dual-band　metamaterials　to　improve　the　efficiency　at　two　different　frequencies　is　verified　by　simulation　and　experiment.　©　2001-2012　IEEE.