Abstract: KTbP₄O₁₂ and aseries of KLa_1-xTb_xP₄O₁₂ crystals were grown from phosphoric acid by evaporation solution method. The experimental conditions of erystal growth were discussed. The crystal structures of KTbP₄O₁₂ were measured by x-ray and infrared spe-ctra. It was found that there exist two types of structure, i. e. α and β structure. The fluorescent spectra of KTbP₄O₁₂ and KLa_1-xTb_xP₄O₁₂ were determined, the former emits strong green fluorescence and may be used as a new laser or luminescence material.