Abstract: Taking a soil slope in an open air iron mine of Hebei as research background，and in view of the impact of groundwater on the slope stability in soil slope engineering，simulations on the landslide of slope affected by groundwater and adding the curtain to support the slope are carried out by using Plaxis 3D.The research results showed that after excavating，the head of groundwater moved downward slightly，and the presence of groundwater undermines the stability of the slope.After the third slope formed，and under the permeation of groundwater，landslides appear in the A1 area of first level slope and A2 area of third level slope，and A4 area appears shear stress of τxy and τyz concentration in the third slope.Finally，according to the slope disaster simulation by groundwater，the waterproof curtain to achieve slope protection can reduce the displacement of landslide disaster and increases the safety factor of the slope.

Key words: Slope stability, Plaxis 3D, Groundwater, Waterproof wall