A　modified　aluminum　phosphate　sealing　agent　was　prepared　by　using　aluminum　dihydrogen　phosphate　and　silica　sol　as　raw　materials,　and　was　used　for　sealing　treatment　of　iron-based　amorphous　coating.　The　phase　of　sealing　agent　was　analyzed　by　XRD.　SEM　and　TG-DSC　were　used　to　characterize　the　surface　morphology　of　the　coating　before　and　after　sealing　and　the　heat　resistance　of　the　sealing　agent.　The　corrosion　resistance　of　the　sealing　coating　was　evaluated　by　electrochemical　measurements.　The　results　show　that　the　modified　aluminum　phosphate　sealing　agent　has　good　heat　resistance,　and　fine　and　close　sealing　layer　was　obtained,　thus　the　corrosion　resistance　is　significantly　improved.　©　2022　Trans　Tech　Publications　Ltd,　Switzerland.