Diatomite/polypropylene composite with excellent sound absorption property was successfully synthesized using diatomite, soluble NaCl, polypropylene, foaming agent and poring agent as precursor materials. The microstructure and mechanical property of the composite materials were characterized by scan electron microscope(SEM) and universal tension test, and the sound absorption performance were evaluated by transfer function impedance tube sound absorption test system. The results demonstrate that when the mass portion of precursor materials fixed at diatomite(30):polypropelene(60)：NaCl(15)：poring agent(2) and foaming agent(20), the composite exhibits excellent compressibility, optimal sound absorption coefficient of 085, and absorption frequency width of above 2000Hz.