Acoustic　microscopy　has　been　widely　applied　in　the　measurements　of　the　mechanical　properties.　However,　the　measurement　of　wave　velocity　on　a　curved　cylindrical　surface　by　acoustic　microscopy　was　seldom　reported.　In　this　paper,　we　adopted　a　large　aperture　line-focus　PVDF　transducer　and　a　defocusing　measurement　system　to　measure　the　velocity　of　a　cylindrical　surface　waves.　The　theoretical　model　was　established　to　study　the　relationship　among　the　propagation　path　of　surface　waves,　the　geometric　parameters　of　a　transducer,　and　the　diameter　of　a　shaft　specimen.　Based　on　theoretical　deduction　and　mathematical　modeling,　theoretical　oscillation　curves　of　phase　difference　were　obtained.　According　to　the　improved　V(f,　z)　analysis　method,　the　V(f,　z)　curves　were　obtained　through　analyzing　experimental　data　at　different　frequencies　by　Fourier　transform.　Then　the　surface　wave　velocity　of　the　cylindrical　tungsten　steel　specimen　(circle　divide　20　mm)　could　be　determined　by　fitting　the　V(f,　z)　curves　with　the　theoretical　curves.　The　measurement　results　were　consistent　with　the　theoretical　values,　indicating　that　the　measurement　method　was　feasible.　This　study　laid　the　basis　for　the　ultrasonic　measurement　of　the　mechanical　properties　on　the　layer-coated　cylinders.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.