When　subjected　to　strong　near-field　pulse-like　ground　motion,　excessive　deformation　of　the　isolation　layer　in　the　mid-story　isolated　structure　occurred,　which　would　result　in　overturning　collapse　of　the　superstructure.　A　protective　system　was　presented　to　limit　deformation　of　the　isolation　layer　by　soft　pounding.　Based　on　the　Kelvin　pounding　model,　mechanical　models　of　the　protection　system　and　the　mid-story　isolated　structure　with　the　protective　system　were　set　up.　The　equations　of　motion　for　the　mid-story　isolated　structure　with　the　protective　system　were　also　derived.　Then,　comparative　analyses　were　conducted　for　the　dynamic　responses　of　the　mid-story　isolated　structure　with　and　without　the　protective　systems.　The　impacts　of　reserve　space　and　limiting　stiffness　on　the　maximum　deformation　of　the　isolation　layer　as　well　as　elastic-plastic　story　drifts　were　explored.　Pounding　responses　were　further　discussed　when　the　strong　ground　motion　was　beyond　preassumption.　The　results　show　that　the　protective　system　does　not　influence　the　isolation　effect　of　the　mid-story　isolated　structure　when　subjected　to　small　ground　movements.　Moreover,　it　is　effective　in　restricting　the　maximum　deformation　of　the　isolation　layer　when　subjected　to　strong　ground　motion,　preventing　collapse　of　the　superstructure　caused　by　isolation　bearings　destruction.　Different　reserve　spaces　and　limiting　stiffness　exert　great　impacts　on　the　maximum　deformation　of　the　isolation　layer　and　elastic-plastic　interstory　drifts.　Even　if　the　strong　ground　motion　is　beyond　preassumption,　the　protective　system　can　also　restrict　the　maximum　deformation　of　the　isolation　layer.　However,　it　is　worth　noting　that　the　failure　mode　may　change　from　instantaneous　collapse　of　the　superstructure　to　plastic　damage　of　the　superstructure.　©　2016,　The　Editorial　Board　of　Journal　of　Basic　Science　and　Engineering.　All　right　reserved.