CuInSe2　(CIS)　has　been　widely　studied　because　of　its　potential　applications　in　photovoltaics,　and　the　phase　structure　is　believed　to　significantly　affect　its　electronic　and　optical　properties.　A　new　wurtzite-type　phase　of　CIS　is　predicted　by　density　functional　theory　calculations　combined　with　evolutionary　methodology.　In　contrast　to　the　common　chalcopyrite　CIS,　Cu　atoms　of　the　predicted　phase　form　new　bonds　with　Se　atoms　derived　from　the　interaction　with　the　second　nearest　neighbor　due　to　symmetry,　and　such　new　bonding　results　in　beneficial　band　structure　for　both　electron　transition　and　transport　because　of　the　delocalized　Cu-d　electrons.　The　calculated　absorption　spectrum　of　the　new　phase　further　reveals　an　improvement　in　light　absorption　index　over　that　of　the　chalcopyrite　phase　under　near-infrared　and　visible　light.　Thus　the　wurtzite-type　CIS　has　advantageous　electronic　and　optical　properties　and　is　a　highly　efficient　active　layer　material　for　high-performance　solar　cells.