Abstract: In order to rapidly and effectively achieve non-destructive testing of the depth, continuity, and possible defects of the anti-seepage wall beneath embankment slope, a microtremor detection method for anti-seepage walls based on natural source surface wave technology was proposed.Firstly ground-penetrating radar (GPR) was used to survey perpendicular to the alignment of the anti-seepage wall, determining its projected axis on the slope surface.Then, a microtremor instrument was installed at the mapping axial line to detect the integrity and defects of the wall.By analyzing the dispersion curve and profile velocity variation characteristics of the measuring points, the depth and defect position of the anti-seepage wall were determined.Through on-site measurement, excavation, water injection test, and comparison verification with elastic wave CT, the results showed that the measured wall depth and the location of wall defects were basically consistent with the traditional elastic wave CT detection results.The measured defect manifested weak or moderate permeability, belonging to the area with poor quality, so it proved accuracy and effectiveness of the testing method.According to the actual measurement results and comparative verification, it is shown that this method can achieve non-destructive quality testing of anti-seepage walls beneath embankment slope, which can provide relatively accurate results with low cost and strong applicability, providing a basis for the judgments of engineering quality.