The　plastic　deformation　and　the　strain　rate　effect　caused　by　the　dynamic　impact　load　may　cause　the　classical　similarity　law　to　no　longer　apply　to　the　mutual　derivation　of　the　impact　resistance　between　the　geometrically　similar　concrete-filled　steel　tube　(CFST)　components.　In　this　study,　four　CFST　components　with　similar　geometric　sizes　were　designed.　The　effect　of　component　size　on　the　impact　response　indexes,　such　as　impact　displacement,　impact　force,　and　energy　absorption　of　geometrically　similar　CFST　components,　was　studied.　It　is　concluded　that　the　above　impact　response　indexes　of　geometrically　similar　CFST　components　do　not　fully　conform　to　the　classical　similarity　law;　that　is,　they　have　a　scaling　effect.　The　scaling　effect　of　impact　displacement　is　mainly　due　to　the　severe　plastic　deflection　deformation　in　the　mid-span　impacted　area　of　large-size　CFST　components.　The　scaling　effect　of　impact　force　is　primarily　due　to　the　slight　normalized　contact　stiffness　in　the　mid-span　impacted　area　and　the　severe　global　stiffness　degradation　of　the　large-size　CFST　components.　The　scaling　effects　of　the　relevant　impact　response　indexes　studied　in　this　paper　are　related　to　severe　plastic　deformation　and　minor　contact　stiffness　of　large-size　components,　and　their　scaling　effect　is　more　significant　with　the　increasing　scale　factor,　which　is　consistent　with　those　for　steel　tube　and　reinforced　concrete　components.　In　addition,　based　on　the　simulation　results　and　drawing　on　the　classical　similarity　law　expression,　the　scaling　effect　model　of　displacement　and　impact　force　for　geometrically　similar　CFST　components　is　preliminarily　established,　which　can　predict　the　calculated　scale　factor　of　impact　response　for　CFST　components.