The　hydraulic　fracturing　process　involves　high　pump　pressure　and　large　displacement,　which　increase　the　risk　of　debonding　on　the　interface　of　the　cement　sheath　and　rock　formation.　Therefore,　in　this　study,　a　three-dimensional　numerical　calculation　model　of　casing-cement　sheath-formation　assembly　was　established,　and　the　failure　mechanism　of　the　bonding　surface　caused　by　fracturing　due　to　fluid　migration　was　investigated.　The　effects　of　the　cement　sheath＇s　Young＇s　modulus　and　Poisson＇s　ratio,　bonding　strength,　perforation　azimuth　angle,　and　non-uniform　in-situ　stress　on　the　anti-debonding　ability　of　the　cement-to-formation　interface　were　analyzed.　Finally,　the　following　conclusions　were　drawn:　The　calculation　results　show　that　the　failure　of　the　bonding　surface　is　greatly　affected　by　the　bonding　strength,　and　its　anti-debonding　ability　significantly　increases　linearly　with　increasing　bonding　strength.　Furthermore,　while　increasing　the　Young＇s　modulus　improves　the　anti-debonding　ability,　the　Poisson＇s　ratio　of　the　cement　sheath　and　the　perforation　azimuth　angle　have　little　effect.　Under　non-uniform　in-situ　stress,　the　anti-debonding　ability　decreases　with　the　increase　of　the　difference　between　the　horizontal　and　vertical　in-situ　stress.　Thus,　the　non-uniform　in-situ　stress　accelerates　the　failure　of　the　bonding　surface.