Organic　epoxy　matrices　have　been　widely　used　in　the　FRP　reinforcing　technique,　but　they　have　serious　disadvantages　of　poor　high-temperature　resistance.　An　inorganic　adhesive　is　invented　to　replace　the　organic　adhesive.　For　the　inorganic　adhesive　at　normal　temperature　and　different　high　temperatures,　the　microstructure　and　phase　composition　are　investigated　by　means　of　X-ray　diffraction　(XRD)　and　SEM　respectively.　Results　show　that　inorganic　adhesive　can　resist　at　least　600　A　degrees　C　high　temperature.　Fire-resistance　performance　of　inorganic　adhesive　can　meet　the　requirements　of　fiber　reinforced　polymer　(FRP)　strengthened　RC　structures.