The　variability　of　structural　engineering　parameters　is　not　accounted　for　in　available　literature　on　seismic　vulnerability　of　underground　frame　structures.　This　study　investigates　the　seismic　vulnerability　of　18　existing　subway　stations　with　different　site　condition,　structural　stiffness,　reinforcement　ratio　and　buried　depth　employing　two-dimensional　(2D)　finite　element　analysis　considering　soil-structure　interaction.　The　peaks　of　structure　inter-story　drift　ratio　under　different　earthquake　intensity　of　different　ground　motion　records　are　ob-tained　from　non-linear　dynamic　time-history　analysis.　Taking　the　inter-story　drift　ratio　as　the　damage　measure　(DM)　and　the　peak　ground　acceleration　(PGA)　as　the　ground　motion　intensity　measure　(IM),　the　seismic　vulnerability　curves　of　18　subway　stations　are　constructed.　The　comparison　of　seismic　fragility　curves　of　different　subway　stations　demonstrates　that　site　conditions　are　critical　to　the　post-earthquake　structure　probability　of　failure.　Furthermore,　representative　seismic　fragility　curves　are　established　based　on　the　data　collected　form　the　computed　results　of　18　subway　stations,　which　can　aid　in　evaluating　the　seismic　performance　of　existing　urban　underground　frame　structures　in　China.　The　results　of　this　study　can　provide　reference　for　the　performance-based　seismic　design　of　urban　underground　frame　structures.