Abstract: Using 20 L spherical explosive device, we investigated the influence of coal dust concentration, ignition energy and particle size on the explosion characteristics of different metamorphic grades coal dust, and analyzed the explosion characteristic difference of different metamorphic grades coal dust under the same conditions. The results showed that the maximum explosion pressure of different metamorphic grades of coal dust have large difference when concentration is 100 g/m³, but the difference is little for 700 g/m³; the maximum pressure and the metamorphic degree of coal dust is negative correlation under the best concentration. The maximum explosion pressure of low metamorphic grade coal dust increased significantly with the increase of ignition energy; the high metamorphic grade coal dust significantly influenced by the ignition energy, the influence weakened until the ignition energy increased to 8 kJ. The burning duration of high metamorphic grade coal dust was affected by the ignition energy obviously. The low metamorphic grade coal dust burning duration is affected by particle size obviously.