Abstract: Transport channels of groundwater or surface water in loess area are controlled by loess joint, loess joint development leads to the loess joint expansion and becomes local large tensile cracks, collapse sliding disasters have occurred frequently under the action of tension in the loess plateau. Through the field investigation and analysis, the collapse loess slope sliding failure can be divided into four stages:slope erosion peeling off stage, the top tensile splitting stage, vertical crack expansion stage and slope overall collapse sliding failure stage. The collapse sliding failure situation was simulated and ion analyzed by using the geotechnical engineering software FLAC^3Dthrough 3d numerical analysis model in combination with practical engineering cases in three rainfall conditions (40 mm/day, 80 mm/day, 100 mm/day) after two raining days, providing an effective analysis paradigm for analysis and control of collapse sliding deformation and failure under the same engineering geological conditions in excavation of loess slope.