The　feasibility　of　efficient　seismic　fragility　analysis　of　underground　structures　using　the　endurance　time　analysis　(ETA)　method　is　investigated.　A　typical　two-story　three-span　subway　station　embedded　in　the　site　class　III　is　used　as　the　prototype.　To　effectively　consider　the　inherent　dispersion　of　as-recorded　earthquake　ground　motions　during　the　simulation　of　endurance　time　acceleration　functions,　the　16%,　50%　and　84%　quantiles　of　response　spectra　of　the　as-recorded　ground　motions　at　the　engineering　bedrock　are　used　as　the　target　response　spectra　to　generate　three　endurance　time　acceleration　functions　using　the　quantile　regression　method　in　the　incremental　dynamic　analysis　(IDA)　for　reference　as　the　input　motions　for　the　nonlinear　soil-structure　interaction　system,　respectively.　The　seismic　fragility　evaluation　of　the　underground　structures　is　performed　based　on　the　ETA　results　and　the　IDA　results.　It　can　be　seen　from　the　numerical　results　that　the　seismic　fragility　curves　obtained　by　the　ETA　are　in　good　agreement　with　those　obtained　by　the　IDA.　Therefore,　the　proposed　ETA　with　full　consideration　of　the　dispersion　of　ground　motions　can　significantly　reduce　the　number　of　nonlinear　dynamic　analyses,　and　ensure　high　accuracy　of　the　computed　results.　Moreover,　the　proposed　ETA　using　a　series　of　discrete　ETAFs　by　the　quantiles　of　response　spectra　of　the　as-recorded　ground　motions　is　a　feasible　alternative　for　the　seismic　fragility　analysis　of　underground　structures.　©　2023　Chinese　Society　of　Civil　Engineering.　All　rights　reserved.