Abstract: The diatomite/polyurethane composites with multiple aperture communicating channels were successfully prepared with diatomite and polyurethane. The effect of the contents of diatomite, foam stabilizer and plasticizer on the microstructure, compressive strength and sound absorption property of diatomite/polyurethane composites were studied. The results show that the diatomite/polyurethane porous composites have good compressive strength and sound absorption property. The diatomite/polyurethane composite with 65wt% diatomite exhibits excellent sound absorption property, the peak of sound absorption is around 1 600 Hz, and the sound absorption coefficient is greater than 0.9. The frequency width, whose sound absorption coefficient is higher than 0.56, is wider than 2 000 Hz.