The　accumulation　of　municipal　solid　waste　incineration　bottom　ash　(MSWI-BA)　not　only　occupies　land,　but　also　leads　to　severe　environmental　pollution.　In　order　to　improve　the　utilization　of　MSWI-BA　and　reduce　carbon　emissions,　the　effect　of　alkali　content　on　alkali-activated　slag　(AAS)　paste　containing　12%　MSWI-BA　under　high-temperature　exposure　was　studied.　The　alkali　contents,　i.e.,　the　mass　of　Na2O　in　the　water　glass,　were　2%-6%　of　the　total　mass　of　the　precursors.　The　weight　loss,　thermal　shrinkage,　and　strength　of　AAS　were　investigated.　The　results　show　that　at　the　same　heat　treatment　temperature,　as　the　alkali　content　increases,　the　flexural　and　compressive　strengths　of　AAS　increase　and　then　decrease,　reaching　the　maximum　at　AAS　with　4%　alkali　content　(NS4).　As　the　alkali　content　increases　from　2%　to　4%,　the　higher　OH-　concentration　reduces　the　Ca　dissolution　of　portlandite　in　MSWI-BA,　resulting　in　a　lower　increase　in　Ca　concentration　than　Si　concentration.　This　leads　to　a　decrease　in　Ca/Si　and　an　increase　in　Al/Si　of　C-A-S-H,　which　is　beneficial　for　improving　the　structural　stability　of　C-S-H　after　high　temperature.　When　the　alkaline　content　increases　from　4%　to　6%,　excessive　matrix　shrinkage　leads　to　an　increase　in　microcracks.　It　was　found　that　NS4　has　the　best　high-temperature　resistance　and　has　good　application　prospects　in　engineering.　©　2024　American　Society　of　Civil　Engineers.