The　current　theoretical　calculation　formula　of　effective　flange　width　of　RC　frame　considering　slab　reinforcement　participation　is　too　complicated　and　inconvenient　for　practical　application.　In　order　to　solve　these　problems,　by　taking　into　account　two　main　factors　influencing　effective　flange　width,　namely,　axial　compression　ratio　and　joint　type,　RC　frames　with　different　axial　compression　ratios　are　designed　and　a　numerical　regression　analysis　on　the　distribution　of　the　effective　flange　width　with　different　joint　types　is　conducted.　Thus,　a　simplified　formula　of　effective　flange　width　is　obtained,　which　is　convenient　for　practical　application.　Then,　some　issues　for　improving　designs　are　suggested　for　the　purpose　of　No　Collapsing　in　the　Strong　Earthquake,　and　the　suggestions　and　the　simplified　formulas　are　verified　by　an　example.　The　results　show　that　(1)　the　simplified　formula　is　simple　and　easy　to　handle,　so　it　is　feasible　in　actual　designs;　and　(2)　the　suggestions　help　to　realize　the　purpose　of　No　Collapsing　in　the　Strong　Earthquake　better.　©,　2014,　South　China　University　of　Technology.　All　right　reserved.