The　theoretical　analysis　and　the　comprehensive　understanding　of　the　seismic　response　characteristics　of　underground　structures　remains　insufficient　in　current　research.　A　series　of　seismic　analysis　are　performed　based　on　the　two-dimensional　finite　element　models　for　the　underground　structures　seismic　response.　The　influencing　factors　of　the　dynamic　characteristics　of　the　surrounding　soil,　the　underground　structures　and　the　soil-structure　system　as　well　as　the　soil-structure　flexibility　ratio　are　quantitatively　considered.　The　numerical　results　indicate　that　for　the　underground　structure,　the　dynamic　characteristics　of　soil-structure　system　are　primarily　attributed　to　the　dynamic　characteristics　of　the　surrounding　soil.　The　seismic　responses　of　underground　structures　mainly　depend　on　the　dynamic　characteristics　of　the　surrounding　soil,　the　volumetric　inertia　forces　of　the　surrounding　soil　caused　by　earthquake　motion　of　the　bedrock　and　soil-structure　flexibility　ratio.　Moreover,　the　peak　linterstory　drifts　of　the　underground　structure　monotonically　and　the　sectional　moment　of　critical　components　decrease　and　increase　with　the　the　soil-structure　flexibility　ratio,　respectively.　While,　the　shear　and　the　axial　forces　of　the　critical　components,　as　well　as　the　peak　average　shear　coefficients　at　the　soil-structure　contact　surfaces,　vary　with　the　increase　of　the　soil-structure　flexibility　ratio.　©　2018,　Editorial　Office　of　China　Civil　Engineering　Journal.　All　right　reserved.