The　simulation　of　forced　deformation　on　retaining　structure　of　an　open-excavated　subway　station　was　carried　out　using　the　software　FLAC3D,　and　a　comparative　analysis　with　field　data　was　accomplished.　The　established　numerical　simulation　methods　are　used　to　analyze　the　horizontal　deformation　of　pile　body　in　different　pre-axial　force　loading　schemes.　The　relationship　between　brace　stiffness　variation　and　retaining　structure　deformation　and　the　relationship　between　variation　of　fender　pile　stiffness　and　retaining　structure　deformation　were　studied.　Results　show　that　1)　steel　support　pre-applied　a　reasonable　axial　force　can　prevent　and　reduce　the　deformation　of　retaining　structure,　and　a　recommended　value　is　80%　of　the　design　value　of　the　axial　force;　2)　pit　top　horizontal　displacement　can　be　reduced　by　increasing　the　rigidity　of　the　steel　support　in　strict　deformation　requisition;　and　3)　the　pile　horizontal　deformation　will　decrease　obviously　with　the　increase　of　fender　pile　diameter,　and　the　effect　will　become　inconspicuous　when　the　pile　diameter　is　to　large.　From　the　perspective　of　controlling　pit　deformation,　structure　designs　should　select　an　appropriate　size　of　the　pile　diameter　and　take　economic　benefit　into　account.