Different　from　making　ordinary　magnesium　phosphate　cements　(MPCs)　with　potassium　dihydrogen　phosphate　(KH2PO4,　PDP),　magnesium　oxide　(MgO,　M)　and　borate　as　retarder,　a　novel　high-strength　Magnesium　Silicon　Potassium　Phosphate　Cement　(MSPPC)　created　by　mixing　dipotassium　hydrogen　phosphate　(K2HPO4,　DHP　(P)),　silica　fume　(SF),　MgO　and　Water　(W),　without　the　use　of　a　retarder,　is　proposed　for　the　first　time　in　this　study.　The　mechanical　properties　of　several　MSPPC　mixtures　prepared　with　different　proportions　of　P/M　(weight　ratio　of　K2HPO4　to　MgO),　W/C　(weight　ratio　of　water　to　cement　paste　(C　=　P　+　M　+　SF))　and　mass　fraction　of　silica　fume　were　investigated.　The　hydration　reaction　mechanism　of　MgO-SiO2-K2HPO4　system　was　analyzed　with　a　variety　of　techniques　including　pH,　X-ray　diffraction　(XRD),　environmental　scanning　electron　microscope-energy　dispersive　spectrometer　(ESEM-EDS)　and　thermo-gravimetric　and　differential　scanning　calorimeter　(TG-DSC).　The　results　show　that　the　cement　paste　with　P/M　of　1/3,　15　wt%　SF　and　W/C　ratio　of　0.16,　the　compressive　strength　was　measured　to　be　113.16　MPa.　The　maximum　flexural　and　compressive　strength　of　MgO-SiO2-K2HPO4　system　is　16.82　MPa　and　101.26　MPa　respectively,　which　is　higher　than　those　of　MgO-K2HPO4　system.　In　MgO-K2HPO4　system,　the　reaction　generates　a　large　amount　of　Mg(OH)(2)　with　poor　gelation　and　expansion,　and　a　small　amount　of　hydration　product　MgKPO4　center　dot　6H(2)O　(MKP)　with　low　internal　crystallinity,　so　the　structural　strength　is　very　low.　Inversely,　in　MgO-SiO2-K2HPO4　system,　silica　fume　plays　an　important　role,　and　the　active　silicon　components　in　silica　fume　are　fully　involved　in　the　acid-base　reaction,　improving　the　mechanical　properties　and　compactness　of　microstructure　of　MSPPC.　Main　hydration　product　struvite-K　has　good　crystallization,　compact　accumulation,　high　density　of　cross-section　structure　and　good　structural　integrity　of　MSPPC.　Expected　secondary　hydration　products　are　magnesium　silicate　gel　(e.g.,　MgSiO3)　and　amorphous　silicon　phosphate　phases,　contributing　to　the　strength　in　MSPPC　pastes.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.