High-density electrical exploration is a direct current exploration method that integrates electrical bathymetry and electrical profile method. It has the characteristics of high density of measuring points, rich information, rapid and efficient [1]. It can effectively solve two-dimensional and three-dimensional geological problems under complex geoelectric conditions, and can be used to simultaneously detect the horizontal and vertical electrical changes of underground media and solve related geological problems. At present, it is widely used in highway engineering geological exploration, especially in the detection of fault fracture zone, lithologic boundary, landslide, karst and cave [2]. In this paper, aiming at the landslide of a cutting slope of a provincial highway in Hebei Province, the type of rock and soil mass and the position of sliding surface of the slope are found out by high-density electrical exploration. The limit equilibrium theory is used to calculate the strength parameters of slope rock and soil, and the stability of slope under three working conditions: natural, rainstorm and earthquake is calculated, and the landslide treatment scheme is given. It can provide some reference for similar landslide treatment.