A study is made of the sound wave propagation through a radiating gas medium that contains solid particles in suspension. The relaxation models are introduced to describe the temporal momentum and thermal nonequilibrium interactions between gas and particles. The gray gas differential approximation is used for radiation. It is found that the radiation induces the attenuation mode, the position of which is varied with the absorption coefficient in addition to the immovable mot by suspended particles. Tbe attenuation because of radiation is greatly influenced by the absorption coefficient of the radiative medium while the dispersion remains almost unchanged. As the absorption coefficient increases, the attenuation mode because of radiation shifts to the higher frequency zone. This radiation effect is significantly reduced as the particle mass loading increases, since the convection becomes much more dominant.