Seismic　vulnerability　models　of　skew　highway　girder　bridges　were　developed　using　the　incremental　dynamic　analysis　approach,　and　simplified　calculation　methods　of　vulnerability　were　discussed.　According　to　the　different　pier　types,　supporting　types　and　design　of　old　and　present　specifications,　the　skew　highway　girder　bridges　were　categorized　into　eight　groups.　The　samples　of　240　benchmark　bridges　were　constructed　with　different　values　of　the　bridge　structural　parameters,　which　were　determined　and　summarized　by　using　the　random　sampling　method.　On　the　basis　of　the　benchmark　samples,　a　series　of　new　bridge　samples　were　created　with　varying　values　of　the　skew　angles.　By　using　the　incremental　dynamic　analysis　method,　the　seismic　vulnerability　of　the　bridge　samples　with　the　same　skew　angles　was　analyzed.　The　relationship　between　the　skew　angles　and　the　seismic　fragility　parameters　was　analyzed.　The　results　showed　that　the　median　value　of　the　seismic　fragility　decreases　when　the　skew　angle　is　increased　while　the　logarithmic　standard　deviation　of　the　seismic　fragility　changes　in　the　opposite　trend.　A　new　correction　formula　of　the　median　value　was　fitted　and　proposed　for　the　existing　skew　highway　bridges　in　China.　Values　of　logarithmic　standard　deviation　were　also　recommended.　A　simplified　calculation　method　for　seismic　vulnerability　of　skew　highway　bridges　was　derived.　The　relevant　result　could　be　beneficial　to　the　seismic　risk　assessment　and　the　retrofitting　codes　of　skew　bridges.　©　2018,　Engineering　Mechanics　Press.　All　right　reserved.