Herein,　a　novel　Bi3+-activated　Ca3Y2Ge3O12　(CYGO)　narrow-band　cyan-emitting　phosphor　was　synthesized.　It　can　be　excited　from　320-420　nm,　and　the　strongest　excitation　peak　is　located　at　370　nm,　which　is　suitable　for　current　near-ultraviolet　(NUV)　chips　perfectly.　The　full　width　at　half　maximum　is　at　52　nm.　By　analyzing　the　crystal　structure　of　the　sample,　we　infer　that　the　Bi3+　ions　replace　the　Y3+　site　to　form　a　highly　symmetrical　BiO6　octahedron.　The　time-resolved　photoluminescence　(TRPL)　spectra　of　CYGO:　Bi3+　reveal　that　the　only　a　single　emission　center　exists　in　the　host　lattice.　A　warm　white　light-emitting　diode　(WLED)　device　with　a　low　correlated　color　temperature　(3148　K)　and　a　high　color　rendering　index　(90.2)　was　fabricated　by　using　the　as-prepared　sample,　and　the　significant　thermal　stability　of　CYGO:　Bi3+　guarantees　its　potential　application　in　WLEDs.　It　is　verified　that　the　structure　with　only　one　crystallographic　Y　site　for　Bi3+　dopant　occupation　and　highly　symmetrical　and　dense　structure　is　conducive　to　realize　narrow-band　emission,　which　will　provide　experience　for　researchers　to　explore　more　Bi3+-activated　phosphors　used　for　high-end　lighting.