Using the wet-discharged fly ash collected from a fly ash storage in Guizhou province as experimental material,the experimental studies were made on the leaching characteristic of alumina in fly ash and the infections of the kinds and concentration of leaching aids,leaching temperature and time on the leaching rate of alumina while using acid and alkali as extracting agent under atmospheric pressure.And also the effects of leaching aids in extracting alumina from fly ash with acid was researched,the mechanism of extracting alumina from fly ash was analyzed.The results showed that only part alumina in fly ash could be extracted without leaching aid under atmospheric pressure,the best extraction rate of alumina was 29.01%,in the acid leaching of fly ash,when adding NH4F as leaching aid the extraction rate of alumina could be improved greatly and increased rapidly with time went on,the best extraction rate of alumina was over 98.68%.