Abstract: In order to leach alumina from high alumina fly ash,different extraction process were studied and compared. Based on the analysis of high alumina fly ash properties,the production process of alkali and acid were compared in the characteristics and applicability,and the process of extracting aluminum oxide with acid from circulating fluidized bed fly ash were described. Some acid extraction methods including sulfuric acid leaching method,basic sulfate method,acid and alkali combination method and one- step acid dissolution method were discussed. The advantages and disadvantages of alumina extraction by acid method were pointed out. The results showed that the acid method on the extraction of alumina from circulating fluidized bed fly ash was feasible.