The invention discloses a melt infiltration casting technology of a foam aluminum alloy. The melt infiltration casting technology is characterized in that salt grains are taken as pore forming agents, the grain diameter of the salt grains is 2-3 mm after being preheated and screened, a ZL102 aluminum-silicon alloy is selected, and an aluminum alloy is molten in a well type resistance furnace; the melt infiltration casting technology comprises the processes of putting processed salt in a die, and preheating the salt in an electric box furnace to certain temperature; pouring aluminum alloy melt in the die, and pressurizing to force molten metal to enter into gaps of grains; removing a tool after solidification, and machining according to a preset shape; dissolving the salt grains, and obtaining foam aluminum. The melt infiltration casting technology disclosed by the invention has the beneficial effects that the structure is uniform, the size is appropriate, and the strength and various mechanical properties are increased to a certain degree.