Abstract: Closed-pore aluminum foam was fabricated by way of adding fly ash first as viscosifier and TiH2 powder as foamer into molten aluminum then stirring it. The results showed that low density and high porosity feature the aluminum foam when the amount of added fly ash is ranging from 3% to 5%, and the aluminum foam will have a good cell structure, i.e., a relatively plain relationship curve among the density and porosity of aluminum foam and particle size of fly ash, if the fly ash particle size is ranging from 61 μm to 147 μm. Using fly ash as viscosifier instead of Ca to increase the viscosity of aluminum melt will not only reduce the cost but also provide high strength for aluminum foam.