Abstract: Based on field investigation and lab tests, the main failure form of the sand loess slope and its impact factors on the northern Loess Plateau are summarized in this paper.Taking for an example from the construction of high-type highways in northern Shaanxi, a series of numerical simulations have been made using the elastico-plastic finite-element method to illustrate the influences of various factors, including the slope form, rainfall and earthquakes, on the stability of sand loess slopes under the conditions of excavation by different engineering works.The simulation results indicate that:with increasing slope angle or slope height, a slope becomes gradually less and less stable;a slope with a stepped form is more stable than that with a linear form, and is favorable for protection;rainfall tremendously influences the stability of a sand loess slope, and especially in the case of water logging at the slope foot, the stain value of the slope foot increases nearly 20 times than that in a normal state; earthquakes can make the values of both the stress and strain at the slope foot increase obviously with the growth of seismic acceleration.The simulation results provide a scientific basis for the high sand loess slope design and hazard control.