Abstract: In order to detect the cracks in track slab effectively and accurately, a two-dimensional finite element model of track slab with surface cracks is established, the action law of Rayleigh wave on surface cracks is analyzed and summarized, and the characteristics of Rayleigh wave time-domain signals received at different crack depths are studied. Based on the principle of Rayleigh wave propagation time difference method, a method for detecting the depth of track slab surface cracks based on Rayleigh wave is proposed, and test results are verified by finite element model. The verification results show that the error of the detection results is relatively small and the accuracy is high, indicating that the detection method is theoretically feasible.