The　impact　of　greenhouse　gas　emissions,　especially　CO2　emissions,　on　the　global　environment　is　receiving　more　and　more　attention.　Most　countries　around　the　world　had　reached　a　consensus　to　reduce　carbon　emissions　after　holding　a　series　of　climate　conferences.　In　2021,　the　buildings　and　construction　sector　accounted　for　around　37%　of　energy　and　process-related　CO2　emissions　globally.　To　mitigate　the　CO2　emissions　produced　by　the　construction　industry,　the　application　of　demountable　steel　structures　that　can　be　reused　is　a　viable　solution.　This　study　investigated　the　design　fundamentals　of　demountable　steel　structures　that　aims　to　reduce　carbon　emissions　by　reusing　the　main　components　of　the　steel　structure.　In　this　paper,　the　demountable　reusability　performance　parameter　γd　of　steel　members　is　proposed　and　used　for　the　reusable　performance　design　of　demountable　steel　members.　An　overview　of　the　mechanical　properties　of　steel　materials　under　static　and　cyclic　loading　are　presented　as　a　basis　for　the　reuse　of　steel　structures.　A　brief　review　of　existing　forms　of　demountable　steel　connection　joints　is　presented　and　the　feasibility　of　reuse　of　demountable　steel　systems　is　explored.　©　2023　Ernst　&　Sohn　GmbH.