A green emitting phosphor Ca₃Y₂(Si₃O₉)₂:Tb³⁺ is synthesized by a high temperature solid state method,and initial materials are CaCO₃(A.R.),Y₂O₃(A.R.),SiO₂(A. R.) and Tb₄O₇(99.99%). Phase formation is determined by X-ray diffraction (XRD) in a Bruker AXS D8adv anced automatic diffractometer (Bruker Co.,German) with Ni-filtered Cu Kα1radiation (λ=1.5406nm).Steady time resolved luminescence spectra,and excitation and emission spectra are detected by a fluorescence spectrophotometer (Hitachi F-4600).Commission International de I′Eclairage (C IE) chromaticity coordinates of samples are measured by a PMS-80spectra analysis system.The un iform diffraction patterns indicate that phase formation of Ca₃Y₂(Si₃O₉)_2is not influen ced by a little amount of Tb³⁺. The excitation spectrum of Ca₃Y₂(Si₃O₉)₂:Tb³⁺ presents an obviou s ^4f75d1broadband absorption (200－300nm) and a weak 4f→4f electronic transition absorption (300－500nm) which corresponds to characteristic excitation of Tb³⁺,and the excitation peak locates at 236n m.With different excitation wavelengths of 236nm,376nm and 482nm,the emission spectra show the same spect ral distribution, and the peak locates at 544nm (⁵D₄→⁷F₅).Tempor al decay of Ca₃Y₂(Si₃O₉)₂:Tb³⁺ as a function of Tb³⁺ concentration is investigated (λ_ex=236nm,λ_em=544nm),and decay time of Ca₃Y₂(Si₃O₉)₂:Tb³⁺ decreases with increasing Tb³⁺ concentration.However,the concentration que nching effect of Tb³⁺ in Ca₃Y₂(Si₃O₉)₂:Tb³⁺ is not observed.