The inorganic aluminum salts such as Ammonium aluminium carbonate hydroxide (AACH with chemical formnla NH4AlCO3(OH)2) and Ammonium aluminium sulfate (AAS with chemical formula(NH₄ )Al(SO₄ )₂ .12H2O) have been known as the excellent precusors to synthesize high-purity aluminabecause the simultaneous removal of NH3, CO2, SO2 and H2O occurs during the thermal decomposition. Probably, this is the cause resulting in the formation of fine aluminium oxide. It is shown that the synthetic method used to prepare the precusors and the method to fabricate alumina from the precusors have a significant effect on the structure, porosity, and dispersion of the resulting aluminium oxide. This work forcus on synthesising of high-purity alumina by heat decomposition of AACH and AAS.