In this paper, porous sound absorbing materials were prepared by using coal gangue as the matrix component, sodium dodecyl sulfate (SDS) as the foaming agent, ammonium chloride as the coagulant, and borax as the sintering aid in combination with gel injection method and foaming method. And the effects of factors such as water-solid ratio, gelling agent content and sintering temperature on the viscosity of slurry, the apparent porosity, sound absorption coefficient and flexural strength of porous sound absorbing material were studied. The porous sound absorbing material with 49.54% apparent porosity, 0.953 sound absorption coefficient in the frequency band of 1 600 Hz and 2.67 MPa flexural strength is finally produced. The results show that the water-solid ratio has significant effects on the viscosity of slurry, the apparent porosity, sound absorption coefficient and flexural strength of porous sound absorbing material, the gelling agent content mainly affects the porosity and thus the flexural strength of the material, and the sintering temperature mainly affects the pore size distribution and thus affects the sound absorption coefficient of the material at different frequency bands. The water-solid ratio of 0.35, gelling agent content of 35% (mass fraction) and sintering temperature of 700 ℃ are the best preparation process parameters.