In　this　paper,　a　noncontact　ultrasonic　testing　method　with　using　a　small　electromagnetic　acoustic　transducer　(EMAT)　in　resonant　mode　is　proposed　for　metal-based　adhesive　debonding　inspection.　The　small　EMAT　with　a　new　magnet　configuration　and　a　small　coil　is　developed　firstly　to　improve　the　spatial　resolution　and　detecting　ability　for　minute　defects.　Different　from　conventional　pulse　echo　method　using　short　pulse　excitation　for　debonding　inspection,　a　new　method　based　on　power　spectrum　estimation　of　the　resonant　ultrasonic　signal　with　long　burst　excitation　is　applied　to　increase　the　signal-to-noise　ratio　(SNR)　and　detecting　ability　of　the　small　EMAT.　Finally,　ultrasonic　C-scan　images　of　specimens　with　various　adhesive　bonding　are　obtained　to　demonstrate　the　capability　of　this　technique.