The　accuracy　of　a　constitutive　model　for　confined　concrete　largely　relies　on　its　capability　to　capture　concrete＇s　dilatancy　behavior.　In　this　paper,　a　non　-orthogonal　flow　rule　(NFR)　is　used　to　reasonably　characterize　the　concrete＇s　volume　change　law　in　relation　to　the　stress　state　without　the　necessity　for　a　plastic　potential　function.　Then,　the　non　-orthogonal　plastic　model　is　implemented　in　the　finite　element　(FE)　software　ABAQUS　using　the　implicit　stress　update　algorithm,　which　employs　the　line　search　method　and　the　numerical　consistent　tangent　stiffness　matrix　to　ensure　the　robustness　and　computational　efficiency　of　FE　analysis.　Finally,　FE　simulations　are　performed　to　evaluate　the　constitutive　model＇s　capabilities　in　actively　and　passively　confined　concrete.　In　the　latter　case,　steel　tubes　restrict　the　concrete＇s　lateral　deformation.　An　analysis　and　discussion　are　conducted　regarding　the　impact　of　dilatancy　behavior　on　concrete　-filled　steel　tube　(CFST)　columns.　The　consistency　between　experimental　data　and　simulation　results　demonstrates　that　the　FE　modeling　with　a　non　-orthogonal　constitutive　model　provides　an　effective　tool　to　describe　the　behavior　of　confined　concrete.