Abstract: Basing on Biot’s theory of acoustic propagation in porous media saturated by fluid correcting the point on ignoring the heat effect between two phases of midia,it is applied Johnson’s model to grain media.The pores in grain both cylindrical pore and parallel slits are considered and a sound transmit model in grain is found.Using the model,the sound absorption coefficient in grain has been calculated.The agreement between calculation and measurement is good.