A　guided　acoustic　wave　technique　for　nondestructive　evaluation　(NDE)　of　the　medical　ultrasound　transducers　is　presented.　A　revised　reflection　coefficient　measurement　technique　is　used　to　obtain　the　dispersion　curves　of　the　Lamb　waves　by　finding　the　local　minimum　of　the　broad　band　reflection　spectrum.　A　set　of　specimens　with　controlled　interface　conditions　between　the　matching　layer　and　the　piezoelectric　layer　are　tested.　The　results　of　experiment　show　there　is　strong　relation　between　the　position　of　the　turning　point　in　the　lowest　order　mode　dispersion　curve　and　bond　quality　of　transducers.