Novel Tm³⁺ and Yb³⁺ codoped bismuth-germanium-lead glass was fabricated and characterized;the glass sample components are 45Bi₂O₃-35GeO₂-20PbO-0.02Tm₂O₃-xYb₂O₃(x= 1.0,1.2,1.4,1.6 and 2.0 mol%). The absorption and upconversion spectra of Tm³⁺ and Yb³⁺ codoped in bismuth-germanium-lead glass were investigated,and upconversion mechanisms of Tm³⁺ in the glass were analyzed. The Judd-Ofelt intensity parameters Ω_t(t = 2,4,6),oscillator strengths,spontaneous transition probability and fluorescence branching ratio of each levels for Tm³⁺ were calculated by Judd-Ofelt theory. Intense blue and weak red emissions centered at 476 and 653 nm,correspongding to the transitions ¹G₄ →³H₆ and ¹G₄→³F₄,respectively,were simultaneously observed at room temperature under 975 nm diode laser excitation. The upconversion emission intensity varies with the power of infrared excitation intensity. A plot of log I_UP VS log I_IR yields a straight line with slope 2.87 and 2.41,corresponding to the 476 and 653 nm emission bands,respectively,which indicates a three-photon process for the blue and red emissions. The results suggest that Tm³⁺ and Yb³⁺ codoped bismuth-germanium-lead glass may be a potential host material for upconversion blue lasers.