Acoustic absorption coefficient of wood fiber/polyester fiber composite material as a porous material was studied. Six factors influencing the sound absorption performance of the composite material including density, thickness, air cavity depth behind the composite material, flow resistance rate, treatment technology were investigated. Results show that：within the scope of the test, when the density of the composite material is 02g/cm3 and the air flow resistance rate is 198×105Pa·s/m2, it has good sound absorption performance. With increasing thickness of the composite material or increasing depth of the cavity behind, sound absorption peak moves to the low frequency; if the composite material becomes denser by treated with needling process, the sound absorption performance enhances obviously; the sound absorption properties of composite materials are reduced by covering the facing material in some extent.