A novel dibarium cadmium diborate, Ba 2 Cd(BO 3 ) 2 , has been successfully synthesized by standard solid-state reaction. Large sheet-like crystal with size up to 20mm×15mm×0.7mm has been obtained using top-seed solution growth method. Ba 2 Cd(BO 3 ) 2 crystallizes in the monoclinic space group C2/m with a=9.6305(4)Å, b=5.3626(3)Å, c=6.5236(2)Å, β=118.079(3)°, Z=2. The crystal structure is composed of isolated [BO 3 ] triangles, [CdO 6 ] octahedra and [BaO 9 ] polyhedra. CdO 6 are vertex-connected with six BO 3 to form infinite ∞ [Cd(BO 3 ) 2 ] layers extending in (001) plane, and two rows of Ba atoms closely occupy two side of ∞ [Cd(BO 3 ) 2 ] layers to forming stoichiometric sheets. IR and transmittance spectrum of Ba 2 Cd(BO 3 ) 2 were reported.