Method for preparing alumina aerogel

The invention relates to a method for preparing alumina aerogel. Firstly, methyl acetoacetate and polyvinyl alcohol are used as raw materials; concentrated sulfuric acid is used as a catalyst; throughester exchange reaction, acetoacetic acid groups are grafted on polyvinyl alcohol to prepare a macromolecule complexing agent; secondly, massive alumina aerogel with high density, high intensity, lowshrinkage rate, high porosity, high specific surface area and concentrated hole diameter distribution is obtained through preparation by using aluminium chloride hexahydrate as an inorganic phase precursor, using the macromolecule complexing agent as an additive, using deionized water as a solvent and using propylene oxide as a network gel inducting agent through the sol-gel process and the supercritical drying and roasting processes. The macromolecule complexing agent is added into the sol-gel process as a gel guiding agent and a dispersant, so that metal aluminum ion sol is uniformly dispersed in the solvent and is