Abstract: The feasibility of the combining geophysical methods with borehole testing to examine the cut-off curtain at a city landfill site was discussed by adopting means of high-density resistivity method, cross-borehole ultrasonic transmission method and borehole television, in the inspection and resorting to multivariate regression in the analysis. The results indicated that high density resistivity method, with its high efficiency, could achieve an overall inspection of the cut-off curtain and delineated suspicious quality defect area. On this basis, cross-borehole ultrasonic transmission method and borehole television, which was intuitive and accurate, could be used to determine the specific characteristic and location of the defects, so as to narrow down the scope of reinforcing. Through multi-scale collocation and multi-parameter verification, this recommended comprehensive method could achieve effective inspection, with different requirements in testing scope and precision of the cut-off curtain.