The　key　issue　of　the　progressive　collapse　(PC)　design　method　is　to　determine　the　PC　resistance　demand　of　the　structure　with　removed　members　due　to　accidental　action.　The　empirical　parameters　that　are　adopted　in　the　design　methods　of　the　existing　codes　are　difficult　to　reasonably　consider　the　effect　of　nonlinear　and　dynamic　behavior　during　the　PC　process　of　building　structures　due　to　the　weak　theoretical　basis.　A　theoretical　framework　for　the　PC　resistance　demand　analysis　of　RC　frame　structures　was　established　based　on　the　energy　conservation　principle.　In　this　framework,　the　relationship　between　the　nonlinear　dynamic　and　linear　static　PC　resistance　demands　for　RC　frame　structures　with　beam　mechanism　to　resist　PC　was　derived.　The　influences　of　nonlinear　and　dynamic　behaviors　were　comprehensively　considered　so　that　the　nonlinear　dynamic　PC　resistance　demands　could　obtained　by　using　the　linear　static　analysis.　At　last,　the　empirical　parameters　in　existing　codes　were　discussed　and　the　proposed　demand　relationship　based　on　the　energy　conservation　principle　was　validated　through　numerical　examples.