In　order　to　reduce　the　earthquake　response　and　prevent　collapse　with　oversize　bottom　displacement　of　soft-first　story　structure,　this　paper　proposed　a　seismic　control　system　for　a　soft-first　story　structure.　The　structure　adopted　a　semi-active　control　method　with　magnetorheological　dampers　in　the　soft-first　story.　Considering　the　adverse　influences　of　vertical　earthquake,　this　paper　established　the　dynamic　model　and　vibration-control　equations　of　structure　under　bi-directional　coupling　earthquake　action.　The　LQR　control　algorithm　was　used　for　the　earthquake　response　analysis　of　the　structure.　The　analysis　results　indicated　that,　the　displacement　response　of　the　structure　concentrates　mainly　on　the　flexible　bottom　layer　in　the　uncontrolled　case.　For　the　semi-active　control　case,　the　displacements　of　bottom　and　top　layer,　acceleration　and　overturning　moment　at　each　layer　are　reduced　significantly.　In　particular,　the　displacement　of　the　bottom　layer　was　reduced　by　60%　and　more.　Compared　with　horizontal　earthquake,　the　seismic　responses　increased　in　the　case　of　coupling　earthquake.　The　increase　of　overturning　moment　is　the　most　obvious.　Therefore,　the　influence　of　vertical　seismic　motion　should　be　considered　in　high　seismic　intensity　region.　The　layer　stiffness　ratio　can　affect　the　control　effect　of　the　structure　more　greatly　and　it　should　be　determined　considering　the　displacement　of　the　bottom,　the　top　acceleration　and　the　overturning　moment.　The　SSI　effect　can　reduce　the　control　effect　of　structure.