The effect of La2O3 doping on the spectroscopic properties of transparent Yb：Y2O3 ceramics was studied. After doping La2O3，the shapes and positions of the absorption and emission peaks of transparent (Yb0.05Y0.95-xLax)2O3 ceramics were almost the same as those of Yb：Y2O3. When La2O3 was added into Yb：Y2O3，the lattice constant of (Yb0.05Y0.95-xLax)2O3 became large and the crystal field strength weaker due to introducing of larger radius of La3+ ion, simultaneously its degree of order is decreased, which results in the decrease of the emission intensities and the emission cross-sections. The emission intensities were reduced greatly for the excessive doping of La2O3 (16at%) in (Yb0.05Y0.95-xLax)2O3 ceramics. On the whole the fluorescent lifetimes of the samples are increased by 45%—60% after doping La2O3.