Performance-based　seismic　design　(　PBSD)　is　known　as　the　future　development　trend　for　structural　seismic　design　codes　of　many　countries.　The　framework　of　PBSD　is　formed　at　present　,　however　,　the　most　important　thing　of　PBSD　,　namely　,　the　definitions　and　quantified　descriptions　of　seismic　performance　levels　for　various　structures　are　still　under　discussion.　From　the　damage　phenomena　of　highway　beam-bridges　,　a　clear　definition　for　the　seismic　performance　levels　of　regular　bridges　under　earthquake　action　is　given　based　on　the　limit　state　concept　for　seismic　design.　The　drift　ratio　of　the　bridge　column　is　employed　as　design　parameter　,　and　its　target　values　for　each　seismic　performance　level　,　including　no　damage　,　minimal　damage　,　medium　damage　,　significant　damage　,　and　collapse　,　are　given　respectively　from　the　statistic　analysis　of　a　large　number　of　experimental　data.　The　results　can　be　used　in　the　performance-based　seismic　design　of　regular　highway　bridges.