A　double　negative　NIM　composed　of　silver　nanowires　structure　at　visible　light　spectrum　with　high　FOM　and　low　loss　was　presented　in　this　Letter.　The　geometrical　parameters　of　silver　nanowires　were　optimized　by　differential　evolution　(DE)　to　decrease　the　transmission　loss　to　the　greatest　degree.　By　using　numerical　simulation　of　a　wedge-shaped　model　and　S-parameter　retrieval　method,　we　found　that　the　DE-designed　silver　nanowires　structure　can　exhibit　a　low　loss　LH　frequency　band　at　the　yellow-light　wavelength　of　595　nm　with　the　FOM　of　45.8,　that　means　it　may　have　practical　applications　because　of　its　low　loss　and　high　transmission.　(C)　2011　Elsevier　B.V.　All　rights　reserved.