The 0.1 mol% Er3+-doped Al2O3 and SiO2-Al2O3 powders have been prepared by the sol-gel method. The results show that the addition of 5 mol% SiO2 into the Er3+-doped Al2O3 suppresses the phase transitions of γ→θ and θ→α. For the 0.1 mol% Er3+-doped Al2O3 powders at the sintered at temperature of 900℃, the broadband photoluminescence (PL) spectrum centered at 1.53 μm in the range from 1.47 μm to 1.63 μm was obtained with the full width at half maximum of 56 nm, and the splitted PL spectra appeared for powders sintered at 1000—1200℃. For the 0.1 mol% Er3+-doped Al2O3-SiO2 powders, the PL spectrum has a single broadband centered at 1.53 μm even when the sintering temperature is as high as 1200℃, and the PL intensity increases by one order of magnitude, because—OH group in the Al2O3-SiO2 powders has been removed completely, compared with that in the Al2O3 powders with and without mixing of SiO2 sintered at the temperature of 900℃.