In　order　to　improve　the　accuracy　of　earthquake　damage　assessment　of　reinforced　concrete　structure,　the　earthquake　damage　assessment　mutation　model　and　four-dimensional　model　of　seismic　damage　analysis　are　established　using　catastrophe　theory.　Firstly,　internal　damage　index,　number　of　inelastic　cycles,　maximum　inter-storey　drift　and　energy-concentrated　quotient　were　taken　as　evaluation　factors.　Value　assignment　and　standardization　of　each　evaluation　index　is　conducted.　The　appropriate　mutation　model　is　selected　to　calculate　the　total　mutation　value　of　seismic　damage　and　comparison　with　the　evaluation　criteria　of　seismic　damage　of　reinforced　concrete　structure,　the　extent　of　structural　damage　is　differentiated.　Secondly,　comprehensive　consideration　of　people＇s　initiative　and　non-linear　characteristics　of　the　system,　a　four-dimensional　seismic　damage　analysis　model　is　build　based　on　the　mutation　assessment　of　earthquake　damage.　Finally,　four　different　structures　are　calculated　and　the　results　are　compared　with　the　ones　of　variable　fuzzy　set　theory,　set-pair　theory　to　verify　the　reasonableness　and　effectiveness　of　the　method.