A　new　mixed　metal　borate,　CdTbGaB2O7,　was　successfully　synthesized　using　the　high-temperature　solution　method　and　its　crystal　structure　was　determined　by　single-crystal　X-ray　diffraction　with　the　following　unit-cell　data:　P42(1)m,　a　=　b　=　7.3487(1)　angstrom,　c　=　4.7247(1)　angstrom,　V　=　255.150(9)　angstrom(3),　and　Z　=　2.　It　belongs　to　a　new　member　of　the　melilite　family,　which　features　a　3D　framework　consisting　of　alternately　stacked　[Ga(B2O7)](n)(5n-)　tetrahedral　layers　and　(Cd2+/Tb3+)　cationic　layers　that　are　interconnected　via　B(Ga)-O-(Cd/Tb)　bridges.　In　addition,　the　solid　solutions　of　CdTb1-xSmxGaB2O7　(0　＜=　x　＜=　0.2)　were　prepared　via　the　solid-state　reaction　method.　The　combined　techniques　of　XRD,　SEM,　IR/Raman,　XPS　and　PLE/PL　were　employed　to　characterize　the　products.　It　was　found　that　the　CdTb1-xSmxGaB2O7　phosphors　simultaneously　showed　green　emission　of　Tb3+　at　545　nm　and　orange　emission　of　Sm3+　at　603　nm　under　excitation　at　370　nm.　The　emission　color　can　be　adjusted　from　green　to　orange-red　by　varying　the　Sm3+　doped　content　via　an　energy　transfer　mechanism.　For　CdTb0.995Sm0.005GaB2O7,　a　QY　of　13.22%　was　obtained,　and　its　emission　intensity　at　423　K　was　94%　of　that　at　303　K.　These　results　show　that　the　prepared　materials　can　act　as　potential　color-tunable　phosphors　for　UV　w-LEDs.