Abstract: With the powdered Al-Si alloy taken as raw material to prepare foam aluminum, the powdered alloy was classified into three powder particle sizes, i.e., d < 74 μm, 74 μm > d < 147 μm and 147 μm < d < 295 μm, and each of them was blended with the foaming agent TiH2 separately. Then they were all pressed into blanks for foaming experiments. As shown in experimental results, the occurrences of TiH2 agglomeration decreases as the powder particle size decrease and, gradually, the agglomerated particles become linear even point-like ones in blank. When the powder particle size decreases to d < 74 μm, all particles present point-like and are distributed uniformly in blank. In this way the high-quality foam aluminum can be obtained with low density, high porosity, thin pore walls, uniformly distributed pores and perfect foam growth.