This　article　takes　the　common　concrete　frame　unit　with　staircase　as　research　object.　We　create　two　kinds　of　finite　element　model,　one　of　which　is　singly　reinforced　staircase　while　the　other　is　doubly　reinforced　staircase,　in　order　to　study　the　impact　of　double　reinforcement.　After　the　modal　and　time-history　analysis,　we　see　that　the　staircase　unit　twists　obviously.　And　the　dynamic　response　of　the　two　models　under　the　minor　earthquake　is　more　or　less　the　same.　When　the　models　confront　with　the　rare　earthquake,　the　damage　situation　is　very　different　with　each　other.　Weak　points　will　be　formed　around　the　section　of　the　cut　rebar,　and　the　doubly　reinforced　staircase　can　make　the　ladder　board　safe　before　the　damage　of　the　frame.　On　both　end　of　the　ladder　abroad,　the　plastic　strain　is　obvious.　Obvious　damage　can　also　be　found　in　ladder　beam,　frame　columns　and　ladder　columns　at　halfspace.