Extreme　loads,　such　as　impacts　and　explosions,　can　cause　significant　damage　to　structural　components.　It　is　crucial　to　thoroughly　examine　the　residual　bearing　capacity　of　structures　subjected　to　these　extreme　loads,　which　will　enable　engineers　to　make　informed　recommendations　regarding　repairs　or　reinforcements,　thereby　preventing　further　damage　and　extending　the　lifespan　of　these　structures.　This　study　presented　an　experimental　and　numerical　investigation　into　the　residual　behavior　of　ultra-high-performance　concrete-filled　high-strength　square　steel　tube　(UHPC-FHST)　members　after　lateral　impact.　A　total　of　15　tests　were　conducted,　including　lateral　impact　tests　using　a　drop　hammer　testing　machine　and　subsequent　axial　compression　tests　using　a　hydraulic　testing　machine.　Of　these,　12　specimens　were　subjected　to　impact　loading　followed　by　residual　capacity　assessment,　while　three　intact　specimens　served　as　control　groups　during　the　axial　compression　tests.　The　failure　modes,　residual　bearing　capacity,　and　load-displacement　curves　of　the　specimens　were　obtained.　Based　on　the　experimental　results,　parametric　analyses　were　performed　to　examine　the　effects　of　the　yield　strength　of　the　steel　tube,　tube　thickness,　impact　location,　and　impact　energy　on　the　residual　mechanical　performance　of　specimens　(i.　e.,　residual　lateral　deformation,　residual　axial　bearing　capacity,　and　residual　ratio).　The　results　showed　that　UHPC-FHST　specimens　exhibited　excellent　resistance　to　lateral　impact,　retaining　a　large　level　of　residual　bearing　capacity　after　impact;　increasing　the　yield　strength　and　thickness　of　the　steel　tube　effectively　reduces　residual　deformation,　and　significantly　enhances　its　residual　capacity　and　energy　absorption　capacity;　overall　flexural　failure　and　following　second-order　effects　weakened　the　residual　capacity　of　mid-span　impact　specimens,　and　shear　failure　and　crack　propagation　of　concrete　were　the　main　causes　of　damage　for　end　impact　conditions.　Finally,　a　finite　element　(FE)　model　was　also　developed　and　validated　using　the　experimental　data.　The　established　FE　model　demonstrated　good　agreement　with　the　test　results,　offering　a　solid　theoretical　basis　for　further　research　on　the　residual　performance　of　UHPC-FHST　members　subjected　to　lateral　impact.