The　efficient　reuse　of　construction　waste　plays　a　vital　role　in　fostering　eco-friendly　practices　in　the　construction　industry.　However,　the　efficient　application　of　recycled　powder　remains　a　significant　challenge　due　to　its　low　reactivity.　In　response　to　this　issue,　this　study　investigates　the　combination　of　recycled　powder　with　slag　to　create　a　recycled　powder-slag-based　geopolymers　(RPSG)　through　alkaline　activation.　To　assess　the　performance　of　RPSG　in　erosion-prone　environments,　the　effects　of　various　sulfate　types,　concentrations,　and　erosion　methods　on　its　sulfate　resistance　were　systematically　evaluated.　Advanced　techniques,　including　SEM,　XRD,　FTIR,　and　MIP,　were　employed　to　analyze　the　microstructural　changes.　The　results　show　that　sulfate-induced　expansive　products　initially　improve,　but　eventually　degrade,　the　performance　of　RPSG　mortar.　The　stronger　reactivity　of　Mg2　+　causes　decalcification,　making　the　erosion　effect　of　MgSO4　solution　more　severe.　The　wet-dry　cycling　process　accelerates　sulfate　penetration　during　the　wet　phase,　leading　to　faster　generation　of　erosion　products,　while　the　crystallization　of　salts　and　shrinkage　during　the　drying　phase　causes　more　significant　degradation.　These　findings　provide　valuable　theoretical　insights　for　applying　RPSG　in　sulfate-rich　environments　and　serve　as　a　practical　reference　for　improving　the　durability　design　of　geopolymer-based　materials　in　engineering　applications.　©　2025