Reaction　mechanism　of　phosphoric　activated　metakaolin　is　studied　by　techniques　of　calorimetry,　ICP-OES,　FTIR　and　NMR　taking　curing　temperature　and　[H3PO4]　as　variables.　A　two-stage　curing　method　including　pre-curing　at　40　degrees　C　for　24　h　and　second　curing　at　60/80　degrees　C　for　another　24　h　effectively　mitigates　thermal-cracking　of　the　obtained　silico-aluminate　phosphate　(SAP)　samples,　whose　maximum　compressive　strength　reaches　120　MPa.　Dealumination　of　metakaolin　in　H3PO4　solution　produces　low　aluminate-containing　silicate　units　and　subsequently　condensation　of　silicate　tetrahedrons　occurs.　Higher　temperature　and　H3PO4　concentration　accelerate　the　two　processes.　After　complete　reaction,　A(VI)　structure　from　metakaolin　disappears　and　the　dissolved　Al　preferably　forms　Al-VI-O-P　units.　During　reaction,　metastable　P-O-P　intermediate　appears　in　SAPs　with　higher　P/Al　ratio　and　finally　transforms　into　Al-O-P　structure　upon　PO43-　consumption.　Phosphate　units　as　P(OAl)(x)(H2O)(4-x)　are　connected　with　Si　or　Al　structure　units.　Major　structural　units　of　the　SAPs　include　Al-O-P,　Si-O-P,　Si-O-Si,　and　Si-O-Al.