To　investigate　the　propagation　behavior　of　Lamb　waves　in　a　thermal　stress　relaxation　type　functionally　graded　material　(FGM)　plate　with　material　parameters　that　vary　continuously　along　the　thickness　the　power　series　technique　which　has　been　proved　to　have　good　convergence　and　high　precision　is　employed　for　theoretical　derivations　The　influence　of　the　gradient　coefficients　of　FGM　on　the　dispersion　curves　is　illustrated　The　numerical　results　also　reveal　differences　between　the　properties　of　Lamb　wave　propagation　in　the　FGM　plate　and　the　corresponding　properties　in　a　homogenous　plate　In　terms　of　results　we　find　that　both　the　normal　and　anomalous　dispersions　exist　in　the　first　and　the　second　modes　of　the　Lamb　wave　that　propagates　in　the　FGM　plate　while　only　the　anomalous　dispersion　is　in　the　first　mode　and　only　the　normal　dispersion　is　in　the　second　mode　for　the　homogenous　plate　The　wave　structure　is　asymmetric　due　to　the　asymmetric　properties　of　the　material　The　dominance　of　in-plane　and　out-plane　displacements　is　different　between　the　metal-rich　and　ceramic-rich　surfaces　All　these　results　give　theoretical　guidance　not　only　for　experimental　measurement　of　material　properties　but　also　for　nondestructive　evaluation　using　an　ultrasonic　wave　generation　device　(C)　2010　Elsevier　Ltd　All　rights　reserved