Research　purposes:　As　using　the　complete　analysis　method　for　beam　on　elastic　foundation　calculate　the　internal　force　as　well　as　the　displacement　of　the　deep　foundation　ditch　enclosure　structure,　the　internal　bracings　was　applied　in　advanced　and　the　calculation　condition　was　inconsistent　with　the　actual　of　the　construction,　a　method　that　considered　the　erection　time　of　the　inner　bracings　was　proposed　in　this　paper　in　order　to　improve　the　calculation　accuracy.　Research　conclusions:　(1)　As　the　bar-system　FEM　complete　analysis　method　for　beam　on　elastic　foundation　was　adopted　to　calculate　the　internal　force　and　the　displacement　of　the　foundation　ditch　enclosure　structure,　the　inner　bracing　was　defined　as　compression-only　bar　unit　with　initial　gap,　and　the　width　of　the　initial　gap　was　equal　to　the　lateral　displacement　of　fender　piles　(or　enclosure　wall)　on　the　point　which　the　inner　bracings　were　applied　at　the　erection　time.　With　that　the　erection　time　of　the　bracings　were　considered　in　the　model,　which　makes　the　internal　force　and　displacement　calculations　of　the　enclosure　structure　accord　the　actual　better.　(2)　Without　considering　the　erection　time　of　the　bracings　while　using　the　complete　analysis　method　for　beam　on　elastic　foundation,　the　calculated　values　of　the　lateral　displacements　and　moments　of　the　fender　piles　(or　enclosure　wall)　were　smaller,　that　was　not　safety　in　practice.　(3)　Research　findings　of　this　paper　can　provide　reference　for　the　design　and　construction　of　foundation　ditch　enclosure　structure.