Through　dynamic　triaxial　test,　the　property　of　strain　degradation　of　embankment　and　composite　foundation　is　studied.　Base　on　this,　dynamic　elasto-plastic　FEM　is　used　to　analyze　the　deformation　properties　of　road.　The　changing　replacement　ratio　in　the　stabilized　range　can　have　impact　on　the　deformation,　and　the　impact　can　be　shown　mainly　by　the　modulus.　However,　the　impact　is　relatively　small.　As　a　result,　while　meeting　the　requirements　of　the　stability　and　the　ceiling　stress　of　the　subsoil,　it　is　not　advocated　to　adopt　the　method　of　increasing　replacement　ratio　of　the　composite　foundation　to　lessen　the　deformation　of　the　embankment.　The　greatest　impact　on　the　embankment　depends　on　the　property　of　the　subsoil,　therefore,　the　whole　soil　lay　may　well　be　strengthened　in　the　case　of　thinner　soft　soil　layer.　The　strengthening　effect　may　be　less　satisfactory　when　the　soft　soil　is　very　thick.　The　changes　both　in　the　depth　and　the　width　of　the　stabilized　range　can　exert　great　influence　on　the　deformation　of　embankment,　in　consequence　of　which　the　deformation　of　embankment　can　be　lessened　through　increasing　the　depth　and　the　width　of　the　stabilized　range　if　the　soft　soil　layer　is　very　thick.