In　this　paper,　effects　of　initial　micro-structures　on　deformation　behaviors　of　commercial　pure　titanium　were　elaborated　by　investigating　the　evolution　of　dislocation　boundary　and　its　adiabatic　shear　sensitivity.　At　the　low　to　medium　stain　rates,　the　main　plastic　deformation　mechanism　of　as-annealed　commercial　pure　titanium　is　dislocation　slipping.　Meanwhile,　geometrically　necessary　boundaries　(GNBs)　with　different　directions　are　generated　and　crossed　with　each　other.　However,　new　dislocation　boundaries　are　formed　in　as-cold　rolled　plates,　which　are　parallel　to　the　initial　ones　induced　by　cold　rolling.　When　the　strain　rate　is　up　to　1000　s-1,　the　initial　dislocation　boundary　playes　an　adverse　role　in　the　adiabatic　shear　sensitivity　of　commercial　pure　titanium.　The　adiabatic　shear　band　is　the　high-speed　deformation　characteristic　micro-structure　in　commercial　pure　titanium.　In　addition,　dynamic　recrystallized　grains　are　generated　in　the　center　of　an　adiabatic　shear　band,　which　is　consistent　with　the　sub-grain　rotation　mechanism.　©　2017　Trans　Tech　Publications,　Switzerland.