In this paper, the bubble’s stability is studied in the process of preparing foam aluminum by powder metallurgy. In this work, carborundum particles, soot powder and carbon fiber are added into pure aluminum powder, respectively. The microstructure of cell wall of foam aluminum, the viscosity and surface tension of melt is investigated. It is discussed the bubble stability which is controlled through adding SiC particles, soot powder and carbon fiber, and the mechanism of bubble’s stability is analyzed. The experiment results showed that the homogeneity of bubble holes of foam aluminum is better than that which is obtained by adding SiC practical and carbon fiber into the raw materials. SEM images showed that SiC particles and carbon fiber distribute evenly on cell wall of foam aluminum. It means that during foaming a lot of SiC particles and carbon fiber distribute diffusively in liquid aluminum melted. It increases the viscosity of melt so that stability of bubble is increased.