A serial of Er₂O₃-doped bismuth-boron-germanium glasses with composition of Bi₂O₃-B₂O₃-GeO₂-Na₂O were prepared by the high-temperature melt-quenching method.And the absorption spectra and fluorescence emission spectra were measured and investigated as a function of erbium ion doping concentration.It is found that there are intense radiation trapping and concentration quenching effect in erbium-doped Bi₂O₃-B₂O₃-GeO₂-Na₂O glasses.With the increase of erbium ion doping concentration,the 1.53 μm fluorescence emission spectrum broadens and the sub-emission peak at 1 560 nm increases,which is analyzed qualitatively with a four-level equivalent model.At the same time,the fluorescence lifetime of ⁴I_13/2 level and the fluorescence intensity at 1.53 μm increase at first,and then decrease with the increase of erbium ion concentration.On the basis of the energy migration model of Dexter theory,the critical distance R₀ for concentration quenching happening and the interaction microparameter C_Er-Er were determined.The value of C_Er-Er in the Er₂O₃-doped Bi₂O₃-B₂O₃-GeO₂-Na₂O glasses was compared with that in other glass hosts.