Non-contact　ultrasonic　testing　of　debonding　in　honeycomb　sandwich　structure　has　been　a　major　challenge　in　industry.　In　this　study,　the　air-coupled　local　defect　resonance　(LDR)　technique　with　coda　wave　analysis　is　proposed　for　nondestructive　testing　(NDT)　of　debonding　in　honeycomb　sandwich　structure.　Numerical　simulations　have　been　conducted　to　visualize　the　LDR　behavior　of　debonding　in　honeycomb　sandwich　structure　by　air-　coupled　excitations,　and　a　decorrelation　analysis　method　is　proposed　for　determining　the　interval　of　coda　wave　from　received　signals.　Results　indicate　that　the　start　moment　of　coda　wave　should　be　determined　as　the　time　corresponding　to　decorrelation　coefficient　exceed　to　0.2　and　the　duration　is　2.5　ms.　Air-coupled　LDR　scanning　experiments　were　conducted　on　the　honeycomb　sandwich　specimens　with　different　deboning.　Experimental　results　indicate　that　the　proposed　technique　is　effective　for　NDT　of　the　debonding　in　honeycomb　sandwich　structures.　The　research　provides　an　efficiency　non-contact　ultrasonic　NDT　method　for　honeycomb　sandwich　structure.