Tb-doped LuAG(lutetium aluminum garnet) and LuSAG(lutetium scandium-aluminum garnet) precursors were synthesized through a co-precipitation process, using ammonium hydrogen carbonate as precipitator. Single-phase cubic LuAG/Tb and LuSAG/Tb phosphors were obtained after calcination at 1000 and 1200 °C, respectively. These powders could be easily sintered into corresponding transparent LuAG/Tb and LuSAG/Tb ceramics in H2 atmosphere at 1850 °C. The PL excitation and emission spectra were recorded for both phosphors and ceramics. Emission spectra of all materials were found to be typical for Tb3+, resulting from radiative relaxation of D level. Both the Tb-doped LuSAG phosphors and ceramics show higher efficient luminescence than LuAG , especially the transparent Tb-doped LuSAG ceramic shows about 150% higher luminescence intensity than transparent Tb-doped LuAG ceramic.