Two　new　terms　about　the　principal　shear　stress　couples　and　their　actions　on　the　principal　shear　planes　are　proposed　through　the　analyses　of　the　Mohr-Coulomb　criterion　and　the　double　shear　criterion.　From　these　points,　a　new　failure　criterion　is　given　based　on　the　prerequisite　that　the　action　of　the　whole　three　principal　shear　stress　couples　acting　on　the　dodecahedron　element　should　be　taken　into　account　in　the　establishment　of　failure　criterion.　Theoretical　analysis　on　the　π-plane　loci　has　shown　that　this　new　criterion　can　basically　reflect　the　nonlinear　failure　and　strength　characteristics　of　the　geomaterials　without　the　defect　of　two　broken　angles　existed　in　the　double-shear　criterion　under　some　stress　states.　In　addition,　the　applications　of　this　new　criterion　are　devoted　to　the　elastoplastic　analysis　of　the　tunnel　and　the　earth　pressure　of　retaining　wall.