Amorphous Cr2O3 materials with high surface areas were prepared via a precipitation process with CrCl3 · 6H2O as the raw material, (NH4)2CO3, NH3 · H2O, and KOH as precipitating agents. Calcination of Cr(OH)3 precipitation at low temperatures (300–400 °C) resulted in amorphous Cr2O3 materials with high surface areas, while high-temperature calcination (500–600 °C) led to crystalline Cr2O3. The hydrogen-adsorption phenomenon was clearly observed in a hydrogen atmosphere on the amorphous Cr2O3 materials with high surface area. The adsorbed hydrogen desorbed at about 550 °C due to the phase transition from amorphous to crystalline. However, this phenomenon was not observed for crystalline Cr2O3.