Abstract: The strength reduction FEM was adopted to analyze slope stability influenced by the gradient of inclined rock ground as well as interface roughness between the fills and the ground.Safety factors,the most dangerous sliding surface as well as their difference from those calculated by the simplified Bishop method were presented.The results showed that for filled slope on inclined intact rock ground,the sliding surface was quite different from circular surface in some cases.There would be considerable error if safety factors were calculated by the simplified Bishop method.Furthermore,for filled slope on inclined intact rock ground with non-full rough interface,there were restriction mechanisms of the inclined rock ground with relatively high strength and weaking mechanisms of the interface,acting on the sliding surface.The former enhanced slope stability,while the latter acted the opposite.The calculation also showed that FEM with strength reduction,applied to the stability analysis of high filled slopes on mountainous ground,could give more realistic shape and position of the sliding surface and consequently more reliable results for the safety factor.In contrast,the conventional limit equilibrium analysis methods,with the usual assumption of circular sliding surface,might give poor results for this type of complicated problems.FEM with strength reduction was simple and efficient.Therefore,its application prospect was more extensive than limit equilibrium method.