Luminescent columbite-type CaNb 2 O 6 crystals undoped and doped with Eu 3+ (CaNb 2 O 6 :Eu 3+ ) and Tb 3+ (CaNb 2 O 6 :Tb 3+ ) have been synthesized at 240°C using hydrothermal method from precursor solutions of inorganic salts. Microscopic examinations reveal that the morphology of the columbite crystals is like thin rods or needles (width: 0.10.3¯m, length 510¯m). The red, green, and blue light-emitting CaNb 2 O 6 -based materials have been prepared. Under the UV light excitation, the as-prepared CaNb 2 O 6 presents a broad and blue photoluminescence (PL) peaked at 452 nm, originated from the niobate octahedral group [NbO 6 ] 7¹ . The columbite-type CaNb 2 O 6 with 12 mol % Eu 3+ synthesized hydrothermally at 240°C shows the strongest PL: weak orange and strong red light, attributed to the 5 D 0 ¼ 7 F 1 and 5 D 0 ¼ 7 F 2 transitions of Eu 3+ , respectively. The intensities of bluegreen and green PL bands originated from the 5 D 4 ¼ 7 F 6 and 5 D 4 ¼ 7 F 5 transitions of Tb 3+ , respectively for the as-prepared CaNb 2 O 6 :Tb 3+ reach the maximum at 10 mol % Tb 3+ , and their PL intensities have been improved by heating at 1000°C in air.