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.