Abstract: In order to find out the slip surface of the highway slope, the transient surface wave and the symmetric four-level electrical sounding method were used for comprehensive geophysical exploration. The position, shape and range of the potential slip surface were successfully identified. The geological section of the sliding body can be efficiently and accurately provided with basic data for landslide treatment design. The application of engineering examples shows that transient surface wave imaging is accurate and intuitive in the identification of sliding surface and, and can provide wave speed parameters; electrical sounding method can provide resistivity parameters of different geological bodies, and can perform transient surface waves. the combination of the two methods can greatly reduce the ambiguity of geophysical prospecting. Combined with a small number of drilling holes, it can provide a more accurate landslide body geological profile, which can play an important role in the detection of unstable highway slopes.