In　this　work,　dynamic　performance　of　precast　reinforced　concrete　beam　connected　by　unbonded　prestressing　tendon　under　impact　loads　was　conducted　using　the　numerical　simulations.　First,　a　detailed　numerical　model　for　cast-in-place　beam　was　established,　and　the　simulation　method　was　verified　with　the　available　test　observations.　Then,　the　numerical　model　of　precast　beam　connected　by　unbonded　prestressing　tendon　was　established.　The　parameters　of　impact　velocity,　impact　position,　concrete　strength　and　prestressing　level　were　investigated,　respectively.　The　results　show　that　the　failure　modes　of　precast　beam　with　prestressing　tendon　is　shear　failure　mode　which　is　similar　to　that　of　cast-in-place　beam　under　impact　loads,　and　a　large　number　of　shear　cracks　are　formed　in　the　mid-span　impact　location.　The　interface　of　precast　beam　is　the　weak　area,　and　it　is　easy　to　form　through　shear　cracks　under　impact　loads.　The　residual　displacement　of　precast　beam　is　smaller　than　cast-in-place　beam　due　to　its　good　self-resetting　ability.　It　should　be　noted　that　with　the　decrease　of　prestressing　level,　peak　displacement,　residual　displacement　and　damage　degree　of　precast　beam　increase　gradually.　Additionally,　with　the　increase　of　concrete　strength,　the　peak　displacement　of　precast　beam　decreases　gradually.