Reduction of unwanted noises is an important issue in the current societies regarding their potential negative impact on the mental and physical health of the peoples. Researchers are trying to find a new method to reduce the damage of this unwanted sound. Accordingly, the use of sound absorbing materials with appropriate acoustic properties has increased in the recent years. In this article, the production of polyurethane foam explained first and sound absorption coefficient of pure PUF has been measured. In order to improve the mechanical and acoustical properties of polyurethane foam, various quantities of Nano-Alumina powder is added to the structure of the foam. The effects of this additive material on the acoustic and mechanical properties of the foam are then measured. In this work, for the first time, the mechanical, physical and acoustical properties of the polyurethane foam improved by Nano-Alumina are studied. Finally, the change of the sound absorption coefficient of the produced composite material is analyzed based on the mechanical and physical experimental results. The sound absorption coefficient of this foam is then measured using two microphone method with Impedance tubes.