Abstract: Fragmentation effect of ore was influenced by dynamic mechanical properties. 16 dynamic compression experiments were conducted on ore A and B by using [?]50 mm Hopkinson bar system to change the impact compressive load. The influence of impact pressure on ore strain rate was analyzed， and the correlation between compressive strength and strain rate was preliminarily studied. The fragmentation degree data of crushed ore were counted and the fragmentation distribution was analyzed. The results show that the dynamic compressive strength of ore B increases by 8.3% when the impact velocity increases by 1 m/s within the range of 12-16 m/s； the dynamic compressive strength of ore A is always lower than that of ore B， and the compressive strength of ore A and ore B increases exponentially with the increase of strain rate； the fragmentation degree of ore increases with the increase of dissipated energy. The larger the size， the lower the overall pass rate of ore B screening fragmentation is than that of ore A， indicating that a large number of inherent micro-defects in ore B accelerate the crack closure in energy absorption deformation. Compared with ore A， ore B shows higher strength and more gentle crushing.

Key words: Rock mechanics, Hopkinson pressure bar, Dynamic mechanical properties, Fragmentation degree