In　order　to　extend　engineering　application　of　nonlinear　ultrasonic　nondestructive　testing　technique　in　wave　structure,　an　experimental　technique　for　excitation　and　reception　directly　of　Rayleigh　wave　by　fixing　piezoelectric　sensor　on　the　edge　of　the　specimen　is　presented,　this　method　is　verified　by　simulation　of　the　finite　element　method(FEM).　By　using　the　experimental　system　and　procedure,　cumulative　effect　of　nonlinear　Rayleigh　waves　is　proved,　nonlinearity　parameters　nearly　linear　increase　with　Rayleigh　wave　propagation　distance　increasing,　which　demonstrates　the　Rayleigh　wave　nonlinearity　parameters　are　sensitive　for　the　changes　of　microscopic　defects　in　the　materials　internal,　and　the　experimental　system　and　procedure　are　reliable.　Finally,　the　surface　fatigue　damage　of　AZ31　magnesium　thick　plate　is　detected　by　nonlinear　Rayleigh　waves.　Although　the　experimental　results　have　some　dispersion,　the　ultrasonic　nonlinearity　parameters　overall　increase　apparently　with　the　fatigue　cycles　increasing,　which　shows　the　Rayleigh　wave　nonlinearity　parameters　for　the　thick　plate　structure　fatigue　life　prediction　have　potential　engineering　applications.　©　2011　Journal　of　Mechanical　Engineering.