As a normal physiological substance, D-galactose (D-gal) can induce a process similar to natural brain aging in vivo and in vitro under excessive intake, so it is widely used to induce brain aging model in China. The model of brain failure induced by D-galactose has the advantages of short time, low cost and significant effect, but its inducting mechanism is complex and diverse, and the relationships between the mechanisms are not clear, which leads to the limitation of the practical application of the model. This article reviews the in vivo metabolism of D-galactose and the various mechanisms of inducting brain aging, as well as the links between the mechanisms, in order to provide reference for the application and development of this model and the in-depth study of brain aging.