Abstract: During mining process in Pingzhuang west open-pit coal，there exists a serious sliding risk at northwest slope influenced by the F₃ fault and weak bedrock layer.To make sure the security of mining-stripping operation，stability researches on northwestern slope were carried out.Based on the strength reduction theory and the rule of D-P，taking transfixion of plastic zone as the slope instability criterion，FLAC^3D software was used to make the numerical simulation on the stability of the anti-dip layered slope at northwest F3 fault in Pingzhuang West open-pit coal.From the analysis of different spatial location of fault and slope，and the unstable failure characteristics of slope which did not have fault in northwest，it is indicated that F3 fault has a great effect on slope slippage pattern and stability in northwest.The potential slide pattern of northwest slope was controlled by F₃ fault and its location in Pingzhuang West open-pit coal.Landslide was caused by the rock gravity，as the rock slides along F₃ fault.Lower rock was squeezed to slide along MD weak layer to the free face，which formed the pushing landslide.Because the existence of fault，landslide was accelerated.The nearer distance of fault from slope surface，the more obvious the effect is.

Key words: Slope stability, Anti-dip layered slope, Faults, Slip mode, Numerical simulation