Magnesium　phosphate　cement　was　made　by　mixing　magnesium　oxide,　phosphates　and　retarder,　forming　a　new　type　of　fast　hardening　and　high　strength　cementitious　materials　through　chemical　reactions　at　room　temperature.　Magnesium　cement　performance　under　impact　force　of　phosphoric　acid　were　studied,　combined　with　SEM　analysis　of　the　reasons　of　magnesium　phosphate　cement　impact　properties　changing.　Research　shows　that　the　impact　resistance　of　magnesium　phosphate　cement　was　poor　and　different　admixtures　have　some　impact　on　its　performance.　There　were　fewer　minor　cracks　and　more　closely　structure　inside　magnesium　phosphate　cement　of　the　better　impact　resistance　by　SEM　analysis.　©,　2015,　Journal　of　Functional　Materials.　All　right　reserved.