Coal dust explosion tests were performed in a 20-L spherical vessel and the post-explosion dust samples were collected for analysis. Various characteristic parameters of each explosion trial were recorded, including maximum pressure, maximum rate of pressure rise, ignition time, and deflagration index. In addition, as a new analytical technique, X-ray diffraction (XRD) was used to analyze the coal dust samples before and after each explosion, and assessments of microcrystalline structures and mineral phases were also performed. The diffraction peaks of post-explosion dust samples were shifted to larger angles and were also sharper and narrower compared to the peaks generated by the original coal dusts. Variations in microcrystalline structural parameters (d(002) and L-002) indicated that the post-explosion specimens had a higher degree of crystallinity and a more ordered crystal structure. Differences in mineral components between the pre-explosion and post-explosion samples were also evident, suggesting phase transformations during the explosions. The above results indicate that XRD analysis can be regarded as a reliable tool to study post-explosion coal dust and provide a new insight on further understanding of coal dust explosion characteristics.