Abstract: This paper focused on the sound absorbing property of foamed aluminum with open pore that was fabricated with vacuum infiltration method, The influences of pore structural parameters and thickness of foamed aluminum with open pore on sound absorbing coefficient were studied. The results showed that the foamed aluminum with open pore made by vacuum infiltration have large sound absorbing coefficient. When its pore diameter decreases, its porosity or its thickness increases, its sound absorbing property will be improved.