Raw material powders of Yb 3+/Al 3+co-doped silica fiber core are fabricated with the SiCl4 hydrolysis method, and the α-silica phase is precipitated after the sintering treatment of removing hydroxyl at 1100 ℃ under the atmosphere of O2. The Yb 3+/Al 3+co-doped silicic acid gels are treated by the normal temperature aging and the high-temperature high-pressure aging in an autoclave. The test results show that the aging treatment can effectively suppress the crystallization of Yb 3+/Al 3+co-doped silica glass raw material powders and the fluorescence intensity and lifetime of Yb 3+ are enhanced. It is validated that the autoclave treatment can shorten the aging time and enhance the fluoresence property, which is an important process of preparing Yb 3+/Al 3+co-doped silica glass raw material powders.