In　order　to　analyze　responses　of　RC　structure　under　secondary　fire　after　the　earthquake,　three　RC　frame　structural　models　were　designed　and　fire　tests　were　carried　out　to　two　specimens　with　the　concrete　crack　width　of　0.5　mm　and　0.1　mm　respectively　which　were　taken　as　the　damage　index　caused　by　earthquake.　The　third　specimen　was　directly　studied　under　fire　test.　The　law　of　concrete　crack　development,　fire　response　and　bearing　capacity　degradation　of　RC　frame　were　preliminarily　studied.　The　experiment　shows　that,　thermal　conductivity　of　concrete　is　increased　after　damage.　Maximum　temperature　of　cross-section　is　also　much　higher;　Ability　of　deformation　recovery　is　decreased.　The　residual　flexural　capacity　of　beam　is　much　lower　than　that　of　column.　At　last,　relationship　between　ω　and　degradation　for　concrete　frame　structure　is　put　forward.