Three　types　of　activators　such　as　sodium　hydroxide,　calcium　oxide　and　triethanolamine　(TEA)　are　used　to　establish　different　activation　environments　to　address　the　problems　associated　with　the　process　of　activating　fly　ash　paste.　We　conducted　mechanical　tests　and　numerical　simulations　to　understand　the　evolution　of　microstructure,　and　used　environmental　scanning　electron　microscopy　(ESEM)　and　energy　dispersive　spectroscopy　(EDS)　techniques　to　analyze　the　microenvironments　of　the　samples.　The　mechanical　properties　of　fly　ash　paste　under　different　activation　conditions　and　the　changes　in　the　microstructure　and　composition　were　investigated.　The　results　revealed　that　under　conditions　of　low　NaOH　content　(1%-3%),　the　strength　of　the　sample　increased　significantly.　When　the　content　exceeded　4%,　the　rate　of　increase　in　strength　decreased.　Based　on　the　results,　the　optimal　NaOH　content　was　identified,　which　was　about　4%.　A　good　activation　effect,　especially　for　short-term　activation　(3-7　d),　was　achieved　using　TEA　under　high　doping　conditions.　The　activation　effect　was　poor　for　long-term　strength　after　28　days.　The　CaO　content　did　not　significantly　affect　the　degree　of　activation　achieved.　The　maximum　effect　was　exerted　when　the　content　of　CaO　was　2%.　The　virtual　cement　and　concrete　testing　laboratory　(VCCTL)　was　used　to　simulate　the　hydration　process,　and　the　results　revealed　that　the　use　of　the　three　types　of　activators　accelerated　the　formation　of　Ca(OH)(2)　in　the　system.　The　activators　also　corroded　the　surface　of　the　fly　ash　particles,　resulting　in　a　pozzolanic　reaction.　The　active　substances　in　fly　ash　were　released　efficiently,　and　hydration　was　realized.　The　pores　were　filled　with　hydration　products,　and　the　microstructure　changed　to　form　a　new　frame　of　paste　filling　that　helped　improve　the　strength　of　fly　ash　paste.