The　hydrophobic　surface　of　extruded　polystyrene　foams　(XPSF)　was　modified　by　UV　curable　adhesives　to　enhance　the　interfacial　bonding　strength　(BS)　with　mortar.　The　UV　adhesive　contained　epoxy　acrylate　resin,　acrylic　acid　and　butyl　acrylate　(denoted　as　EAB).　After　EAB　modification,　the　BS　value　in　dry　state　(BS-D)　increased　from　0.050　MPa　of　unmodified　XPSF　with　mortar　to　0.210　MPa.　Then,　3-aminopropyltriethoxysilane　(APTES)　was　further　introduced　into　EAB　to　form　the　water-resistant　coatings　(denoted　as　EABT)　to　enhance　the　BS　value　in　wet　state　(BS-W).　By　optimizing　the　composition,　the　maximum　BS-D　and　BS-W　of　0.216　and　0.158　MPa　in　7-day　curing　were　obtained.　The　bonding　mechanism　illustrated　that　the　modified　XPSF　was　chemically　bonded　with　mortar.