Progressive　collapse　of　building　structures　can　be　induced　by　accidental　fire.　Static　analysis　is　widely　used　in　the　traditional　fire　resistance　analysis　of　buildings　to　predict　the　limit　state　of　structures　subjected　to　fire.　However,　the　mechanical　behaviour　of　structures　exceeding　the　limit　state　should　be　simulated　in　a　progressive　collapse　analysis.　At　this　stage,　some　structural　members　fail　and　then　lead　to　a　dynamic　progressive　collapse　process.　Therefore,　the　traditional　static　analysis　can　not　accurately　simulate　the　progressive　collapse　of　building　structures　in　fire.　On　the　other　hand,　conventional　dynamic　method　is　also　difficult　for　the　research　or　engineering　application　of　fire-induced　progressive　collapse　because　of　the　huge　unnecessary　computing　workload　in　accordance　with　the　long　time　fire　action.　In　order　to　solve　these　problems,　an　equivalent　time　method　is　proposed　to　significantly　reduce　the　time　cost　of　dynamic　analysis　for　the　fire-induced　progressive　collapse.　With　this　method,　an　internal　computing　time　is　used　for　the　heat　transfer　analysis,　as　well　as　the　coupled　thermal-mechanical　analysis　at　the　material　level;　whilst　an　external　computing　time　is　used　for　the　mechanical　progressive　collapse　analysis　at　the　structural　level.　The　simulation　for　an　8-story　planar　RC　frame　shows　that　when　a　proper　ratio　of　the　internal　time　to　the　external　time　is　selected,　the　proposed　method　can　accurately　simulate　the　damage　of　fire　to　the　structural　material,　and　at　the　same　time　significantly　reduce　the　computing　time　of　progressive　collapse　analysis.