Theoretical　and　experimental　researches　are　carried　out　on　non-destructive　evaluation　of　mechanical　properties　of　layer-coated　cylinders,　which　is　of　great　significance　for　the　surface　quality　detection　and　evaluation.　In　this　work,　the　lab-developed　acoustic　microscopy　and　the　line-focus　PVDF　transducers　are　applied　in　the　defocusing　measurement　with　different　coating　thickness.　Considering　the　nonlinear　relationship　between　the　propagation　path　of　the　surface　wave　and　the　defocusing　distance,　the　geometric　parameters　of　the　PVDF　transducer　are　related　to　the　defocusing　distance　and　the　cylindrical　radius.　A　correlation　analysis　method　is　developed　based　on　V(f,　z)　analysis　to　extract　the　dispersion　curves.　Combined　with　the　characteristics　of　wave　propagation　of　coating　materials,　the　acoustic　parameters　of　cylindrical　coating　materials　are　inversed　by　fitting　the　theoretical　curves　to　the　experimental　ones,　using　the　particle　swarm　optimization-based-simulated　annealing(PSO-SA)　algorithm.　Hence,　the　elastic　constants　of　coatings　are　obtained.　The　experimental　results　indicate　that　the　measurement　results　well　match　the　theoretical　counterparts,　which　prove　that　this　method　is　reliable　and　accurate.　This　method　provides　a　powerful　technique　for　the　non-destructive　evaluation　of　cylindrical　coating　materials.　Furthermore,　it　can　be　a　great　tool　for　evaluation　of　material　properties　in　Surface　Engineering.　©　2017,　Science　Press.　All　right　reserved.