The fluorescence properties of Er3+:4I13/2→4I15/2 transition in tellurite glasses have been investigated as a f u nction of the Er3+ concentration. The critical distance R0 for whic h concentration quenching will happen, and the interaction microparameter C Er-Er in tellurite glasses were determined on the basis of the energy migr ation model of Dexter theory. The value of CEr-Er in the proposed tel lurite glass was compared with that in other glass hosts. Finally, the concentration quenching mechanism described using a model based on energy transfer and quenching by hydroxyl groups was presented.