The　failure　patterns　of　the　large　span　steel　structure　(LSSS)　at　all　levels,　from　the　system　level　to　the　member　and　joint　levels,　can　be　attributed　to　the　large　deformation　instability.　The　safety　control　indices　for　LSSS　mainly　include　the　load　carrying　capacity　and　the　deformation　ductility.　However,　the　current　Chinese　steel　design　code　and　other　relating　design　specifications　lack　the　provisions　that　provide　a　systematic　regulation　on　the　safety　performance　indices　for　LSSS　at　the　joint　and　system　levels.　Based　on　a　large　number　of　engineering　design　practices　and　experimental　studies,　structural　analyses　were　firstly　carried　out　considering　the　geometrical　non-linearity　and　material　non-linearity.　Then　the　load-stress,　load-strain　and　load-displacement　whole　process　curves　were　obtained.　The　strength　and　deformation　ductility　of　LSSS　were　carefully　investigated.　On　this　basis,　the　control　indices　of　strength　and　deformation　ductility　for　systems　and　joints　of　LSSS　under　elastic　and　elasto-plastic　analysis　were　set　up　and　a　ductility　performance-based　method　for　LSSS　design　was　put　forward.