Coal fly ash is the major coal solid waste in thermal power plants. Extracting of aluminum from coal fly ash is environmentally and scientifically significant for disposing and utilizing waste materials and exploring new aluminum source, and has attracted extensive attention recently. A new technology of preparing high purity alumina by leaching fly ash with ammonium hydrogen sulfate aqueous is introduced. The characterization of following products was carried by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 adsorption-desorption method Field emission scanning electron microscopy (SEM) and. The results show that the alumina precursor with discs or strip morphology can be obtained by controlling the corresponding technological parameters. The mesoporou γ-Al2O3 obtained by calcining AACH at 500 °C for 4 h exhibits high specific surface area of 571.32 m2/g, a pore volume of 0.75 cm3/g and pore size of 6.15 nm. Alumina particles transform to the spherical shape with increasing calcining temperature. The alumina with particle size in diameter about 60 nm and purity not less 99.92% is obtained by calcining AACH at 1200°C for 2h. The so called alumina product may be used as catalyst carrier material, composite material, fine ceramics and other aspects.