This　work　investigates　the　difference　in　the　fragmentation　characteristics　between　the　microscopic　and　macroscopic　scales　under　hypervelocity　impact,　with　the　simulations　of　Molecular　Dynamics　(MD)　and　Smoothed　Particle　Hydrodynamics　(SPH)　method.　Under　low　shock　intensity,　the　model　at　microscopic　scale　exhibits　good　penetration　resistance　due　to　the　constraint　of　strength　and　surface　tension.　The　bullet　is　finally　embedded　into　the　target,　rather　than　forming　a　typical　debris　cloud　at　macroscopic　scale.　Under　high　shock　intensity,　the　occurrence　of　unloading　melting　of　the　sample　reduces　the　strength　of　the　material.　The　material　at　the　microscopic　scale　has　also　been　completely　penetrated.　However,　the　width　of　the　ejecta　veil　and　external　bubble　of　the　debris　cloud　are　narrower.　In　addition,　the　residual　velocity　of　bullet,　crater　diameter　and　expansion　angle　of　the　debris　cloud　at　microscopic　scale　are　all　smaller　than　those　at　macroscopic　scale,　especially　for　low-velocity　conditions.　The　difference　can　be　as　much　as　two　times.　These　characteristics　indicate　that　the　degree　of　conversion　of　kinetic　energy　to　internal　energy　at　the　microscopic　scale　is　much　higher　than　that　of　the　macroscopic　results.　Furthermore,　the　MD　simulation　method　can　further　provide　details　of　the　physical　characteristics　at　the　micro-scale.　As　the　shock　intensity　increases,　the　local　melting　phenomenon　becomes　more　pronounced,　accompanied　by　a　decrease　in　dislocation　atoms　and　a　corresponding　increase　in　disordered　atoms.　In　addition,　the　fraction　of　disordered　atoms　is　found　to　increase　exponentially　with　the　increasing　incident　kinetic　energy.