Yb³⁺-doped silica fiber is a key component of high power fiber laser and its core material is Yb³⁺-doped silica glass. The performance of Yb³⁺-doped silica fiber is closely related to the properties of core material. This paper reviews our research progress on Yb³⁺-doped silica glass co-doped with Al, P, F, B and Ce fabricated by a sol-gel method and subsequent high-temperature sintering and effect of co-doping elements on the optical, spectroscopic and structural properties of Yb³⁺-doped silica glass, to provide a reference for optimizing the laser performance of Yb³⁺-doped silica fiber. More researches should focus on the relationship between properties of optical fiber and structure of Yb³⁺-doped silica glass in the future.