The　effect　of　soil　nonlinearity　on　dynamic　soil-structure　interaction（SSI）is　studied　using　the　coupled　finite-element　and　indirect-boundary-element　method.　In　the　2D　model，the　far-field　soil　is　simulated　by　the　indirect　boundary　element　method（IBEM）and　the　near-field　soil　is　simulated　by　the　finite　element　method（FEM）；the　soil　nonlinear　behavior　is　taken　into　account　by　the　equivalent　linearization　model.　The　case　analysis　of　the　Millikan　Library　building　shows　that　soil　nonlinearity　plays　a　significant　role　on　SSI.　After　considering　soil　nonlinearity，the　base　shear，the　structure　drift　and　the　system　frequency　are　all　reduced　rapidly　compared　to　responses　that　in　linear　cases.　The　reduction　degree　of　the　nonlinear　SSI　responses　is　more　significant　in　the　cases　of　larger　amplitude　of　the　seismic　waves　or　stronger　nonlinearity　of　the　soil.　©　2022　Science　Press.　All　rights　reserved.