Predicting　the　low-velocity　impact　response　of　the　prototype　based　on　the　scaled　test　results　is　one　of　the　significant　topics　in　structural　design　and　protection.　Thus,　reliable　similarity　laws　are　required　to　bridge　the　dynamic　similarity　between　models　and　prototypes.　In　this　study,　numerical　modeling　was　carried　out　by　considering　plastic　damage　and　strain　rate　effects.　Then,　the　impact　responses　of　four　series　reinforced　concrete　beams　satisfying　traditional　similarity　laws　were　analyzed.　The　largest　beam　section　size　reached　600　mm　x　1000　mm.　The　scaling　effects　on　the　impact　force　profiles　(comprising　three　Types)　and　reaction　force　profiles　of　the　beam　were　investigated.　Several　characteristic　points　were　defined　for　the　available　simplified　profiles　of　impact　and　reaction　forces.　It　is　shown　that　the　scaling　effects　on　each　characteristic　are　not　consistent.　As　the　theoretical　scale　factor　increases,　the　characteristics　such　as　the　peak　impact　force,　the　positive　peak　of　the　reaction　force,　and　its　plateau　satisfy　the　traditional　similarity　law,　whereas　the　characteristics　such　as　the　impact　force　duration　and　the　negative　peak　of　the　reaction　force　do　not.　Therefore,　modified　dynamic　scale　factors　for　the　characteristics　of　impact　and　reaction　force　profiles　from　models　to　prototypes　were　proposed.　Based　on　the　suggested　scaling　laws,　the　simplified　profiles　of　impact　and　support　reaction　forces　of　the　prototype　can　be　predicted.　It　is　expected　that　it　will　help　researchers　to　conduct　experimental　studies　and　optimized　designs　on　structural　impact　resistance.