In　this　paper,　vibration　control　of　a　huge　subway　platform　with　upper　structure　subjected　to　seismic　excitations　is　discussed　through　theoretic　analysis.　Based　on　characteristics　of　the　complex　system,　the　up　and　the　subjacent　part　of　the　system　along　the　control　layer　is　simplified　as　a　SDOF　system,　respectively.　Thus　the　structure　system　is　simplified　as　a　two-degree　(not　considering　the　mass　of　control　devices)　or　three-degree　(considering　the　mass　of　control　devices)　vibration　system.　The　mechanical　model　and　the　dynamic　equations　of　the　system　are　established　and　solved.　Meanwhile,　the　association　and　the　difference　between　the　base-isolated　system,　the　TMD　system　and　such　a　control　system　are　also　discussed.　The　results　show　that　the　seismic　response　can　be　significantly　reduced　by　choosing　the　stiffness　and　damping　of　the　superstructure　properly　are　variables.