In　the　case　of　assuming　that　the　debonding　interface　layer　was　a　thin　fluid　layer　and　taking　the　structural　boundary　conditions　into　consideration,　we　derived　the　expressions　of　ultrasonic　reflection/transmission　coefficients　in　a　thick　adhesive　layer　composite　structure　with　debonding　and　slip　defects　under　water　immersion　conditions　based　on　the　global　matrix　method.　In　addition,the　finite　element　method　was　used　to　calculate　the　ultrasonic　reflection/transmission　coefficients　when　the　bonding　interface　is　debonded　and　slipped　in　the　bonding　structure.　The　theoretical　calculation　and　simulation　results　are　in　complete　agreement.　The　influences　of　the　position　of　the　interface　defects　(upper　or　lower　interface　of　the　adhesive　layer)　and　defect　types　(slippage,　debonding)　on　the　ultrasonic　reflection　characteristics　were　also　studied.　The　results　show　that　if　the　incident　angle　and　frequency　of　the　sound　wave　are　set　appropriately,　the　perfected　bonding,　slippage　and　debonding　interfaces　can　be　distinguished.