The　limit　equilibrium　method　is　usually　used　in　stability　analysis　of　reinforced　roadbed.　It　considers　the　function　of　reinforcing　material　as　equivalent　tension　and　neglects　Interaction　betweens　oil　and　reinforcing　material.　Based　on　the　roadbed　engineering　construction　of　phase　III　engineering　in　Beijing-Chengde　Highway,　a　grid-soil　contact　element　has　been　constructed　to　research　the　application　of　geogrid　in　semi-filling　and　semi-excavating　roadbed,　and　the　failure　mode　and　stability　of　roadbed　according　to　the　numerical　simulation　result　is　also　discussed　in　this　study.　We　put　forward　the　optimization　scheme　of　reinforcement　of　using　geogrid　in　semi-filling　and　semi-excavating　roadbed　engineering.　©　2011　IEEE.