A large number of mountain disasters were induced by Wenchuan Earthquake, and as one type of them, the deformation and failure modes of anti-dip slopes were influenced by overburden. Under the condition of no overburden, the collapse will mainly occur; while under the overburden condition, it is the shallow slump mainly occured. Taking the landslide of Wangjia Mountain in Longmenshan Town, Pengzhou City as an example, the anti-dip slopes were stimulated by using the finite element method in this study, where the influences of overburden on deformation and failure of anti-dip slopes were analyzed under the static condition with seismic load effect. The related analysis showed that significant influences of overburden existed on the deformation and failure of slopes, resulting into great increments of slope displacement, stress and sliding distance. The analytical results were consistent with the characteristics that the large-scale deformation and failure of anti-dip slopes mainly occurred on the slopes with overburden in the Wenchuan Earthquake.