In Er3+/Yb3+ codoped Na2O-ZnO-PbO-GeO2-TeO2 (NZPGT) glasses, effective ~1.5mm infrared (IR) emission was investigated under 980nm excitation. Judd-Ofelt intensity parameters Wt (t = 2, 4, 6) had been calculated to be 6.78´10-20, 1.54´10-20, and 1.17´10-20cm2, respectively. The IR emission full width at half maximum (FWHM) is 73nm, and the maximum stimulated emission cross-section (se) is derived to be 7.53×10-21cm2. A figure of merit (FOM) as the product FWHM´se is adopted to evaluate the gain bandwidth. The comparison of FOM in different glasses indicated that Er3+/Yb3+ codoped NZPGT glasses were potential materials in developing broadband optical amplifier.