In　self-healing　cement-based　materials,　the　interface　between　microcapsules　and　cement　matrix　determines　the　probability　of　microcapsules　triggered　by　cracks,　which　affects　the　self-healing　effect.　Aiming　at　the　interface　bonding　problem　of　water　absorbent　microcapsules,　the　surface　of　epoxy/calcium　alginate　microcapsules　was　modified　with　silane　coupling　agent　KH550　to　improve　the　interface　bonding　between　calcium　alginate　microcapsules　and　cement　matrix.　The　X-ray　photoelectron　spectrometer　and　inductively　coupled　plasma　emission　spectrometer　were　used　to　characterize　the　bonding　condition　of　silane　coupling　agent　on　the　surface　of　microcapsules.　The　pore　structure　of　cement-based　materials　was　analyzed　by　mercury　injection　method,　and　the　impermeability　and　self-healing　effect　of　cement-based　materials　were　tested.　The　results　show　that　the　silane　coupling　agent　forms　the　chemical　bonding　with　the　calcium　alginate　on　the　outer　wall　of　the　microcapsule.　The　interface　between　the　microcapsules　and　the　cement　matrix　is　effectively　improved.　The　number　of　harmful　pores　in　the　cement　matrix　is　reduced,　and　the　number　of　harmless　and　less　harmful　pores　increases.　The　impermeability　and　self-healing　effect　of　cement-based　materials　are　improved.　©　Zaslavsky　Publishing　House.　All　rights　reserved.