The luminescence properties of Tb3+ in La1-xTbxTa7O19 solid solution were systematically examined. The emission spectra are similar for ultraviolet (UV) excitation and cathode ray (CR) excitation. The ratio of D-5(3)/D-5(4) emission intensity decreased with increasing Tb3+ concentration. The observation is well explained by the cross-relaxation mechanism between Tb3+ ions. On UV excitation, the emission intensity of. Tb3+ has a maximum near x = 0.9 of La1-xTbxTa7O19 This result is quite different from that where concentration quenching is found at a lower value of rr:on CR excitation. The mechanism of concentration quenching is discussed by the energy transfer or migration between Tb3+ in the nearest neighbor sites and the self-quenching introduced by the exchange interaction via TaO7 and TaO8.