Stability　analysis　for　three-dimensional　(3D)　earth　retaining　structures　(ERSs)　is　a　pivotal　problem　in　geotechnical　engineering,　particularly　for　seismically　active　areas.　In　this　work,　the　3D　ERSs　in　soil　are　assessed　for　seismic　stability　following　a　nonlinear　strength　criterion.　The　power-law　strength　criterion　and　seismic　forces　are　introduced　into　the　3D　ERS　stability　analysis　via　a　multi-cone　failure　mechanism.　The　coefficient　of　active　soil　pressure　Ka　is　derived　by　exploiting　the　energy　balance　equation.　The　upper　bound　solutions,　that　is　the　maximum　results　of　the　Ka　are　captured　with　the　help　of　a　genetic　algorithm.　The　validity　of　the　current　study　is　verified　by　a　comparative　analysis,　and　the　effects　of　soil　strength　nonlinearity,　the　seismic　forces,　the　soil-wall　friction　angle,　the　height,　the　inclined　angle　and　the　3D　geometric　traits　of　ERSs　on　the　Ka　solutions　and　the　stability　of　ERSs　are　investigated.　It　is　indicated　that　the　height　and　the　3D　geometric　characteristics　of　the　ERSs　will　not　only　determine　the　Ka　solutions　directly,　but　also　influence　the　impact　of　soil　strength　nonlinearity　on　the　stability　of　ERSs.　Strength　criteria　should　be　chosen　combining　the　geometric　characteristics　of　ERSs　to　derive　more　critical　estimates　on　the　stability　of　3D　ERSs.　Additionally,　a　range　of　seismic　and　static　stability　charts　used　for　preliminary　design　are　put　forward　as　well.