The　objective　of　this　study　is　to　develop　a　simplified　numerical　model　that　can　be　used　to　accurately　and　quickly　conduct　collapse　analysis　of　a　reinforced　concrete　(RC)　frame　impacted　by　a　vehicle　obliquely　at　45　degrees.　The　simplified　numerical　model　included　introduces　a　simplified　RC　frame　and　a　simplified　vehicle.　For　the　simplified　RC　frame,　a　mixed　modelling　technique　was　used,　in　which　structural　components　that　experienced　serious　damage　were　simulated　using　detailed　elements,　while　the　retained　structural　components　were　simulated　by　larger　elements.　A　constraint　algorithm　of　nodal　rigid　body　in　LS-DYNA　was　adopted　to　guarantee　the　displacement　compatibility　of　two　kinds　of　element.　For　the　simplified　vehicle　model,　the　spring-mass　system　was　improved　on　the　basis　of　the　energy　conservation　principle　to　represent　the　vehicle　in　a　45　degrees　impact.　Combining　the　simplified　RC　frame　model　and　vehicle　model,　the　impact　response　of　an　RC　frame　subjected　to　vehicle　impact　was　studied　and　compared　with　the　results　of　a　detailed　RC　frame　model　impacted　by　a　detailed　vehicle.　The　validation　confirmed　that　these　introduced　simplifications　could　significantly　improve　the　computational　efficiency　and　ensure　the　computational　accuracy　for　the　collapse　analysis　of　an　RC　frame　subjected　to　vehicle　impact.