In　emergency　decision　making　(EDM),　it　is　necessary　to　generate　an　effective　alternative　quickly.　Case-based　reasoning　(CBR)　has　been　applied　to　EDM;　however,　choosing　the　most　suitable　case　from　a　set　of　similar　cases　after　case　retrieval　remains　challenging.　This　study　proposes　a　dynamic　method　based　on　case　retrieval　and　group　decision　making　(GDM),　called　dynamic　case-based　reasoning　group　decision　making　(CBRGDM),　for　emergency　alternative　generation.　In　the　proposed　method,　first,　similar　historical　cases　are　identified　through　case　similarity　measurement.　Then,　evaluation　information　provided　by　group　decision　makers　for　similar　cases　is　aggregated　based　on　regret　theory,　and　comprehensive　perceived　utilities　for　the　similar　cases　are　obtained.　Finally,　the　most　suitable　historical　case　is　obtained　from　the　case　similarities　and　the　comprehensive　perceived　utilities　for　similar　historical　cases.　The　method　is　then　applied　to　an　example　of　a　gas　explosion　in　a　coal　company　in　China.　The　results　show　that　the　proposed　method　is　feasible　and　effective　in　EDM.　The　advantages　of　the　proposed　method　are　verified　based　on　comparisons　with　existing　methods.　In　particular,　dynamic　CBRGDM　can　adjust　the　emergency　alternative　according　to　changing　emergencies.　The　results　of　application　of　dynamic　CBRGDM　to　a　gas　explosion　and　comparison　with　existing　methods　verify　its　feasibility　and　practicability.　©　2020,　The　Author(s).