Abstract: In order to investigate the influence of external conditions on explosion characteristic parameters of coal dust, we carried out systematic experiments in 20 L spherical explosive device, and discussed the influence of different ignition energy on explosion, compared the explosion suppression effect of two kinds of inert medium between CaCO₃ and Al(OH)₃, and investigated explosion behaviors of coal dust with different water content. The results show that the maximum explosion pressure is linear rise; explosion pressure firstly increases and then decreases with the increasing of coal dust concentration; adding inert CaCO₃ and Al(OH)₃ can effectively reduce coal dust explosion pressure. The explosion suppression results of adding Al(OH)₃ is better than adding CaCO₃; explosion pressure increased with the reducing of water content.