Up-conversion of 45PbF 2 –45GeO 2 –10WO 3 oxy-fluoride glasses co-doped with Yb 3+ and Er 3+ ions were prepared by fusion method through melting at 1223K and then annealing at 653K for 4h. Transmittance of the undoped host glass was beyond 73% in a range of 0.6–2.5μm and the co-doped glasses still provided good transmittance beyond 50%. Refractive indices of the host and co-doped glasses were 1.517 and 1.650, respectively. Blue, green and red fluorescence spectra were observed in a range of 400–700nm under 980nm diode laser excitation. Up-conversion spectra at about 410, 518, 530 and 650nm were assigned to the 4f electron transitions of 2 H 9/2 → 4 I 15/2 , 2 H 11/2 → 4 I 15/2 , 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 of Er 3+ ion, respectively. The mechanism of energy transfer between Yb 3+ and Er 3+ ions in the glass was analyzed. Raman shift shows the non-radiative relaxation of the glass sample is low.