Acetone adsorption on the Ni-CaO catalyst has been investigated using temperature-programmed desorption technique under ultra-high vacuum condition. Acetone adsorbed on the 2wt%Ni-CaO catalyst decomposes mainly to carbon monoxide and hydrogen at 380 ℃, 590 ℃ and 790 ℃ simultaneously. With the increase of Ni loading, the acetone decomposition temperature shifts to higher temperature region suggesting that the catalyst basicity change due to Ni addition causes the weaker interaction between acetone and Ni-CaO than in case of pure CaO. So we could suggest that the added Ni decreases the Ni-CaO catalyst basicity to make the internal acetone bond strong resulting in less dissociation of acetone to hydrogen.