采用激光超声技术探究带涂层圆柱形零件表面缺陷的检测原理，基于有限元法建立了带有涂层金属圆柱形零件表面的数值模型，展开了带涂层圆柱表面缺陷激光超声特性的研究。通过数值模拟分析了涂层以及表面缺陷深度与激光超声表面波之间的关系。研究结果表明：涂层的存在会造成圆柱表面瑞利波的色散，且色散程度与涂层厚度有关；当表面有裂纹存在时，经过缺陷反射后的信号中存在与缺陷深度相关的特征波峰RR与RS，并且RR与RS到达的时间差△t与缺陷深度之间存在着分阶段线性关系，临界点与涂层厚度有关；经过缺陷后的透射信号的频域波形幅值随着缺陷深度的增加而减小。

In order to explore the characteristics of surface defects of coated cylindrical parts and laser ultrasonic surface wave, a numerical model of coated cylindrical parts was established based on the finite element method.The relationship between coating,surface defect depth and laser ultrasonic surface wave was analyzed by numerical simulation.The results show that:the existence of the coating will cause the dispersion on the coated cylindrical surface, and the dispersion is related to the thickness of coating; when there is a crack on the surface, characteristic peaks RR and RS can be found in the reflective surface Rayleigh wave, and there is a phased linear relationship among the time difference Δt and the depth of the defect, and the demarcation point is related to the coating thickness; the amplitude of the frequency domain waveform of the transmitted signal after the defect also decreases as the depth of the defect increases.