In　order　to　describe　the　seismic　performance　of　half-through　concrete　filled　steel　tubular　(CFST)　arch　bridge　from　the　perspective　of　probability,　the　theoretical　analysis　method　was　used　to　establish　the　seismic　fragility　curves　of　CFST　arch　bridges.　Based　on　the　investigation　of　the　basic　data　of　more　than　100　half-through　CFST　arch　bridges　built　in　China,　common　ranges　of　basic　design　parameters　and　general　construction　of　the　arch　bridges　were　concluded.　Based　on　the　case　study　of　a　three-span　half-through　CFST　tied　arch　bridge　without　thrust,　a　typical　bridge　sample　was　built.　The　vulnerable　components　of　the　typical　bridge　sample　under　seismic　combination　were　determined　by　linear　elastic　static　analysis　and　time-history　analysis,　while　the　performance　levels　of　each　component　were　defined.　The　theoretical　seismic　fragility　curves　of　the　typical　bridge　sample　were　established　by　incremental　dynamic　analysis　(IDA)　method.　The　results　show　that　for　the　three-span　non-thrust　system,　the　main　vulnerable　components　are　the　connecting　piers　and　the　pot　bearings　installed　on　the　connecting　piers,　and　the　arch　ribs,　suspenders,　tied　rods　and　foundations　are　generally　not　damaged　under　seismic　action.　Compared　with　Type　I　site　condition,　the　damage　probability　of　the　structure　under　Type　II　site　condition　is　relatively　high.　The　effect　of　site　conditions　is　greater　with　higher　intensity　of　seismic　ground　motion.　©　2019,　Department　of　Journal　of　the　China　Railway　Society.　All　right　reserved.