Abstract: The special engineering properties of the red beds which distribute extensively in Sichuan basin often result in serious geological disasters. Through the characteristic analysis of deformation and destruction of the slope in the connection line between Wengong town and Chengren Highway, failure mechanism of the slope under the influence of excavation and precipitation is concluded as creep-sliding and fracturing. Further by FLAC^3D numerical analysis, the deformation and failure mechanism of slope were verified. The results point out that cracking damage at the trailing edge as well as the shear slip failure at the front of landslide were caused by the excavation unloading and rainfall. For this type of slope, reinforcement measures should be taken in time in the part above the cutting slope after excavation to prevent rainfall infiltration from softening the soil and intensifying deformation and failure of the landslide.