Aluminum hydrates were synthesized using $AlCl_3$.$6H_2O$as starting material by precipitation method. The phases of obtained powder were amorphous, boehmite, bayerite, nordstrandite depending on the pH of solutions. Aluminum hydrates transformed to $alpha-Al_2O_3$via $gamma$- $Al_2O_3$,$delta$- $Al_2O_3$,and $ heta$-$Al_2O_3$,and particle sizes were grown by increment of heating temperature. The TEX>$gamma$</TEX>- $Al_2O_3$ powder was coated on intermediate layer of ceramic membrane by the dip-coating method, and unsupported membrane was also prepared for comparison. The supported layer showed porous structure with small grains, but the unsupported layer revealed interconnected larger grains. Grain growth is dominant in the unsupported layer than in the supported one.