Based on the analysis of the engineering geological conditions of the giant loess landslide, it was induced to slide again caused by slope-cut during the highway construction. The site investigation and study revealed that the stress inside the thick loess slope has been changed slowly, which resulted in tension fracture settlement in the crown, bedding slip in the middle part, compressive deformation in the foot of the body. Intermittent sliding characteristics and inherited damage are analyzed in detail. According to geological analysis, calculation and FEM simulation, the giant loess landslide is instable, especially on the condition of heavy rainfall. The road is still hazardous and active and effective treasures should be taken to prevent and control.