AbstractTo reveal the dynamic impact of rock bursting induced by the thick and hard roof of gravel as key stratum fractured, based on the key strata and rock control theories, combined with the mechanical load-based dynamic loading with the Law of Conservation of Energy in a system, this paper analysed the static stability and the processing of energy conversion within the system when the key stratum was fracturing. And the key stratum dynamic model of fracturing was established. The results indicate that large amounts of strain energy would be forced into the rock during the process as the key stratum fractures and becomes unstable. The greater the dynamic load factor is, the more elastic energy is forced into the lower rock strata of the key stratum, and the more obvious the dynamic impact of the lower rock strata would be. The size of the dynamic load factor relates to the aspect ratio of key rock masses, the thickness of the overburden, the mining height, the height of the fragmentized rock at the bottom of key stratum and the compaction coefficient of the fragmentized rock under the static during loading conditions. According to the calculation of actual work, the results are consistent with the field tests approximately. The results can provide references to similar conditions.