Abstract: High strain-rate uniaxial compressive loading tests were produced in the modified split Hopkinson pressure bar(SHPB) with pulse shaper on granite samples.It was shown that the failure of the granite cylinder was typical tensile splitting failure mode by sudden splitting parallel with the direction of uniaxial compressive loading at different strain rates.Besides,it was concluded not only the strength of granite increased,but also the fragment size decreased and fragment numbers increased with the increasing strain rate.To analyze quantitatirely the failure phenomena,the numerical calculation based on a dynamic interacting sliding microcrack model was adopted to investigate the influence of microcracks with the different initial crack length,crack angle,crack space and friction coefficient on the macro-mechanical properties of granite under different strain rates.Accordingly,the strain-dependency of the compression strength and the fragmentation degree of granite was explained reasonably.