In　order　to　mitigate　problems　associated　with　environmental　pollution,　alkali-activated　nickel　slags　(AANSs)　may　be　used　as　an　alternative　to　cementitious　material.　However,　the　understanding　of　their　mechanical　properties　and　microstructure　is　currently　very　limited.　This　paper　therefore　explores　the　influence　of　different　types　and　contents　of　three　solid　alkali　activators,　Na2SiO3,　NaOH,　and　Na2SiO3/Na2CO3,　on　the　compressive　strength　of　one-part　AANS.　Their　microstructure,　hydration　components,　and　pore　structure　are　analyzed　by　means　of　a　scanning　electron　microscope,　an　energy-dispersive　spectrometer,　an　X-ray　diffractometer,　an　infrared　spectrometer,　and　a　mercury　analyzer.　The　results　show　that　the　AANS　with　an　Na2SiO3/Na2CO3　activator　has　a　denser　microstructure,　lower　porosity,　and　a　smaller　pore　size　when　compared　with　the　AANS　with　the　Na2SiO3　or　NaOH　activators.　Consequently,　the　compressive　strength　of　the　Na2SiO3/Na2CO3　sample　reached　a　higher　compressive　strength　(96　MPa)　than　that　activated　by　Na2SiO3　or　NaOH.　This　strength　is　optimal　as　well　as　more　economical　as　Na2O,　which　increased　from　0.107　mol　to　0.123　mol,　contributes　little　to　compressive　strength.　The　final　part　of　the　article　discusses　an　optimal　design　for　the　engineering　application　of　one-part　AANS.　©　2020　Liwei　Xu　et　al.