Aiming　at　the　surface　defect　detection　of　the　thick-walled　pipe,　a　PZT　based　the　flexible　comb　Rayleigh　wave　transducer　was　proposed.　Firstly,　the　finite　element　simulation　was　carried　out　to　optimize　the　parameters　of　element　interval,　element　width,　element　number　and　element　length.　The　influence　of　the　element　number　and　the　element　length　on　the　directivity　of　the　transducer　was　studied.　The　tailing　of　the　Rayleigh　wave　signal　was　suppressed　by　optimizing　the　backing　materials　and　the　backing　thickness.　Secondly,　a　new　type　of　flexible　comb　Rayleigh　wave　transducer　was　developed　according　to　simulation　results.　The　characteristic　of　the　transducer　was　tested,　and　experimental　results　agreed　well　with　the　simulation.　According　to　the　simulation　and　optimization,　the　tailing　of　the　Rayleigh　wave　were　shrinked　and　the　exciration　energy　was　concentrated,　with　the　element　interval　of　λR　(λR　equals　the　Rayleigh　wavelength),　the　element　width　of　λR/2,　and　the　number　of　elements　of　5.　The　experimental　result　showed　that　the　comb　Rayleigh　wave　transducers　possessed　good　directivity　and　capability　of　examination　of　the　surface　defects　of　thick　walled　pipes.　©　2017,　Science　Press.　All　right　reserved.