Er3+-doped bismuth-based glasses with the composition of Bi2O3-B2O3-Si2O were prepared by conventional high-temperature melting and annealing method. The 1.5 μm band spectroscopic properties of Er3+ were measured and analyzed, and the research focused on the transient response of 1.5 μm band fluorescence under the pulse excitation at 975 nm. The results show that there was a rise- and fall-response process of Er3+ fluorescence corresponding to the up and down-edge of 975 nm pulse, respectively, and the response rate is dependent on the lifetime of Er3+ at 4I13/2 level. With the increase of Bi2O3 component content, the lifetime of Er3+ decreases resulting from the energy transfer aroused by OH groups in the glass, and the response becomes faster accordingly.