Abstract: Loess is not a homogenised material. Because of it's interrupting of sediment, changing of environment and acting of various physical and chemical factors, loess has been formed a layered structure-between tomposed of loess, soil, and puppet. This layered structure plays a very important role in the stability of high loess slope. Based on the research of high loess slope in Tong-Huang First Level High Way, the author studied the relation between layered structure and it's stability. of the high loess slope also, based on the test of the properties of each layers, stability of the slope is evaluated and simulated with Finite Element Method.