The closed-pore aluminum foam was manufactured by direct foaming with blowing gas into the molten aluminum,and the effects of the processing parameters on the pore structure and the stability of aluminum foam were investigated.The aluminum foam with mean pore size and more than 90% porosity can be manufactured by means of Al-Si alloy as raw materials and Al2O3 particles as adhesion agent with foaming temperature at 750～780 ℃ and particle volume fraction of 10%～15% as well as gas flux at 0.5～1.5 L/min.The production verifies that the gas injection foaming is a promising method to produce aluminum foam with high porosity simply and efficiently.