Abstract: Various particle sizes and its explosive residues were tested using 20 L spherical explosive device, and the effect of particle size on the explosive conditions and explosive products of coal dust and solid residues was analyzed under different coal dust concentrations and ignition energy conditions. The results show that with the increase of coal dust particle size, the explosion of coal dust and its solid residue requires more stringent explosive critical conditions (higher coal dust concentration and higher ignition energy); the degree of hole development and particle fragmentation is much higher than that of large particle size coal dust and its explosive residue, compared with the explosive product of large particle size and its solid residue, and the content of O, Si two elements and the content of C element is lower in the explosive product of small particle size coal dust and its solid residue.