The preparation of alumina with large surface area, certain phase and porosimetry has always been one of important researches. A new method using much less sucrose (the molar ratio of sucrose to Al 3+=0 5) was developed to prepare γ-Al 2O 3 with large surface area and high thermal stability. Firstly,ammonium hydroxide was dropped to aqueous solution of aluminum nitrate and sucrose. The resulted precipitate in suspension was heated until a homogeneous gel was obtained. Then the gel was dehydrated at 110 ℃ to get a fluffy black precursor. Finally, γ-Al 2O 3 with A=345 m2/g was prepared by calcining the precursor at 600 ℃ for 24 h. The precursor and the obtained γ-Al 2O 3 were characterized by DTA-TG, N 2 adsorption-desorption isotherms, XRD and TEM. According to the dispersion behaviors of organic compounds on supports, the related mechanism was discussed.