在介绍了表面波检测混凝土裂缝深度的可能性及检测方法的可行性后，阐述了利用有限单元法研究平面瑞利表面波检测混凝土裂缝深度的原理，以及测试分析方法。研究表明有裂缝时相位差φ比无裂缝时要大，且φ与振动频率ω不成线性关系。存在一特征频率，在该频率处相位差φ变化大，有效深度系数约为０５。 After introducing the possibility of surface crack detecting concrete crack depth and the feasibility of testing method, the principle of using planar Rayleigh surface wave to detect concrete crack depth by finite element method is expounded, and the test and analysis method is expounded. The results show that the phase difference φ is larger than that of the crack without cracks, and φ is not linear with the vibration frequency ω. There is a characteristic frequency at which the phase difference φ varies widely with an effective depth coefficient of about 0.5.