Er3+/Tm3+ codoped lead-free bismuth silicate glasses were successfully prepared by conventional melt-quenching method. The energy transfer mechanism and energy transfer efficiency between Er3+ and Tm3+ ions were investigated through absorption spectra and fluorescence spectra. The results show that the Tm3+: 1.8 μm emission is enhanced by codoping Er3+ ions upon 800 nm and 1550 nm excitation. The corresponding maximum emission cross sections are estimated to be 6.7×10－21 cm2 and 7.3×10－21 cm2 on the basis of Fuchbauer-Ladenburger equation, respectively. Simultaneously, both values of 1.8 μm emission bandwidth are about 250 nm. The direct energy transfer microscopic parameter of Er3+: 4I13/2→Tm3+: 3F4 process is calculated to be 16.8×10－40cm6/s. This phenomenon results in the relatively stronger 1.8 μm emission using a 1550 nm pumping source.