Research　purposes:　With　the　development　of　planning　and　construction　of　railway　passenger　dedicated　line　in　our　nationwide,　it　is　more　common　for　railway　bridges　to　pass　through　karst　areas.　As　a　result,　how　to　analyze　the　effect　of　grouting　reinforcement　on　the　settlement　of　pile　foundation　and　determine　a　reasonable　grouting　reinforcement　scheme　has　become　the　problem　of　designing　a　pile　foundation　of　railway　bridge　in　karst　areas.　Based　on　pile　foundation　engineering　of　a　railway　passenger　dediciated　line　in　karst　area,　genuine　Lizheng　Software　that　based　on　code　was　used　to　analyze　the　effect　of　different　grouting　reinforcement　scheme　on　the　settlement　of　pile　foundation,　at　the　same　time　reasonable　grouting　reinforcement　scheme　was　selected.　Research　conclusions:　(1)　Only　grouting　karst　cave　can　control　the　tilt　of　pill　foundation　well,　but　it　can　not　control　the　settlement　of　pile　foundation　effectively.　(2)　Only　grouting　the　soil　layer　at　pile　tip　can　control　the　settlement　of　pile　foundation　effectively,　but　it　can　not　control　the　tilt　of　pill　foundation　well.　(3)　Grouting　both　karst　cave　and　the　soil　layer　at　pile　tip　not　only　can　control　the　tilt　of　pill　foundation　well,　but　also　can　control　the　settlement　of　pile　foundation　effectively,　as　the　result　it　is　a　better　grouting　reinforcement　scheme.　(4)The　above　conclusions　can　provide　reference　for　the　engineering　of　pile　foundation　grouting　reinforcement　in　karst　area.