The Ce3+/Tb3+ doped oxyfluoride glasses with high Gd[(1-x)Lux]2O3 concentration are prepared by high temperature melting method. The densities, transmission spectra, excitation spectra, emission spectra under ultraviolet (UV) and X-ray excitations and decay curves of Ce3+ ions are measured and analyzed. The scintillating glasses have excellent performance of high light output. The densities of the glasses are greater than 5.8 g/cm3. The Ce3+ ions can sensitize the luminescence of Tb3+ ions. The energy transfer mechanisms of the Ce3+/Tb3+ doped scintillating glasses are analyzed by the I-H theory model. The energy transfer rate and energy transfer efficiency between Ce3+ and Tb3+ ions are calculated by the fitting data and theoretical formula. The results indicate that the energy transfer mechanism is non-radiative energy transfer, the energy transfer rate is proportional to the square of the Tb3+ ions concentration, and energy transfer efficiency increases with the concentration of Tb3+ ions.