Taking　a　practical　five-story　frame-structure　with　opening　floor　as　background,　the　finite　element　analysis　software　ETABS　is　used　to　perform　analysis　of　the　first-floor　isolation.　Time-history　analysis　for　the　structures　showed　that,　vibration　reduction　effect　of　the　superstructure　is　obvious　under　7　degree　earthquakes.　The　substructure　(isolated　columns)　is　still　in　elastic　deformation　stage　under　7　degree　rare　earthquakes,　which　proves　that　isolation　technology　on　the　top　of　columns　can　improve　the　seismic　behavior　of　the　first-floor　weak　frame-structure.　Meanwhile,　mechanical　analyses　and　seismic　design　of　the　isolated　columns　are　performed.　The　results　indicated　that　rational　design　ensures　the　structure＇s　seismic　safety.　©　(2012)　Trans　Tech　Publications.