Microstructural characteristics of high-purity titanium during dynamic compression at low-medium strain were studied by optical microscopy (OM), electrical back-scattered diffraction (EBSD) techniques and transmission electron microscopy (TEM). The results show that the original grains are gradually refined by twin-twin, twin-dislocation and dislocation-dislocation interactions. The predomiant twinning system is {11-22} twinning at the beginning of deformation, {10-12} twinning become to the main twinning modes when strain reached 0.2. The orientations of each twinned grain are altered by twinning that further facilitate dislocation glide in interior grains. Though dislocation slip and twinning always work together to coordinate macroscopic plastic deformation, the deformation process of high-purity titanium during dynamic compression is experienced dislocation slip to deformation twinning and dislocation slip again.