In order to develop an excellent explosive inhibitor for Al-Mg alloy dust explosion, the micron grade Mg(OH)2 (MH) was selected as the explosive suppressant, and the surface modification was carried out with the coupling agent KH-550(.gamma.-Aminopropyl triethoxysilane). The flame propagation suppression experiment was carried out with the improved Hartmann tube experiment system, and the explosion pressure suppression experiment was carried out with the 20 L spherical explosion experiment system. The experimental results show that the modified MH powder has better dispersion. MH explosion suppressor can effectively reduce the flame height, flame propagation speed and explosion pressure, and the modified MH has better inhibiting effect. The main reason is that the specific surface area of modified MH powders is larger than that of unmodified MH powders, so the heat absorption capacity and cooling effect of modified MH powders are better. (C) 2021 Elsevier B.V. All rights reserved.