To understand the complex dynamic response of deformation and fracture of metal cylindrical shell at high-strain rates loading,the cylinder shells fabricated from 50 SiMnVB steel and 40 CrMnSiB steel were selected as the objects for study. The ultra-high speed photographic technology and AUTODYN-2 D finite element software are applied to research the dynamic deformation of shell at high strainrates,which obtaine the variation of radial displacement and velocities of outer-wall from the shell,and the fragment mass distribution and fracture fragmentation behavior of the resulting fracture fragments are analyzed. The results reveal that the phase of cracks penetrating the entire casing wall thickness occurs within the time range of 20-25 μs,and the velocity of 40 CrMnSiB steel shell is increased by 8. 1%,compared with that of 50 SiMnVB steel shell. Moreover,the distribution of fragments width is of Gaussian-distribution,the fragmentation degree of fragments formed by 40 CrMnSiB steel shell is more serious,and the number of fragments with mass of more than 0. 1 g is increased by 49% compared with that of50 SiMnVB steel shell.