In　order　to　further　enhance　the　high　temperature　resistance　of　alkali-activated　slag　(AAS)　and　promote　the　consumption　of　municipal　solid　waste　incineration　bottom　ash　(MSWI-BA),　0–12　wt%　of　slag　was　replaced　by　MSWI-BA,　and　the　influence　of　MSWI-BA　content　on　the　high　temperature　resistance　of　AAS　paste　was　studied.　The　performance　of　AAS　paste　containing　MSWI-BA　after　high　temperature　was　investigated,　including　weight　loss,　thermal　shrinkage　and　strength.　Meanwhile,　the　microstructure　of　AAS　was　investigated　to　unravel　the　high　temperature　resistance　mechanism.　Results　show　that,　for　the　same　temperature,　the　flexural　and　compressive　strengths　of　AAS　rise　initially,　and　then　fall　as　MSWI-BA　content　rises,　reaching　their　highest　value　in　AAS　with　6%　MSWI-BA.　The　flexural　and　compressive　strength　of　AAS　with　6%　MSWI-BA　at　400　°C　are　31.3%　and　17.9%　higher　than　that　of　AAS　without　MSWI-BA,　respectively.　When　MSWI-BA　content　is　less　than　6%,　the　presence　of　portlandite　and　hydrotalcite　in　MSWI-BA　increases　the　alkali　concentration　and　accelerates　the　hydration　reaction,　which　promotes　the　formation　of　C-A-S-H　gel　with　high　degree　of　polymerization.　Besides,　the　hydrogen　generated　by　the　reaction　of　elemental　aluminum　in　MSWI-BA　and　OH−　can　improve　the　pores　connectivity　of　matrix,　and　reduce　the　water　vapor　pressure　and　shrinkage,　thus　inhibiting　matrix　cracking.　However,　due　to　its　low　activity　and　porous　characteristics,　an　excessive　amount　of　MSWI-BA　(＞6%)　leads　to　a　decrease　in　the　amount　of　C-A-S-H　and　a　significant　increase　in　porosity,　thus　reducing　the　strength　of　AAS.　©　2023　Elsevier　Ltd