Abstract: The KHCO3 / red-mud composite powder was successfully prepared by the anti-solvent method for gas explo- sion suppression. The aluminum industry solid waste red mud was used as the support,and the traditional suppressant KHCO3 was used as the active species. The as-prepared samples were analysized by the techniques of XRD,TG-DSC, SEM,TEM. The analysis results indicated that the composite powder possesses the special core-shell structure,which has an impact on inhibitory property. The suppression property of the as-prepared sample for CH4 explosion was tested by a 20 L spherical explosion experimental system. The results show that the potassium bicarbonate / red mud composite powder has better suppression property than that of pure red mud or pure potassium bicarbonate. The explosion pres- sure of 9. 5% methane-air premixed gases was reduced by 37. 5% with 30% loaded content. The maximum value of pressure rising rate was reduced by 93. 2% ,and the sensitive period of the explosion was extended from 25 to 250 ms. The explosion suppression mechanism of this potassium bicarbonate / red-mud composite powder was also investigated.