Abstract: The geological condition of a high and steep slope can be complex. Its weak structural planes can well develop. The excavated height and ratio are high. The excavated faces are many for the sake of the space of the deformation. There are many failure evidences at the slope. Based on investigation of engineering geological conditions, this paper examines the slide plane feature and location of a large scale landslide on a highway. It analyzes the development process and stability status of the landslide. According to the borehole data, the rock mass and sliding surface parameters are obtained. Combining with inverse computation of parameters, the sliding surface’s c and φ values are obtained. Finally under the condition of abnormal(rainstorm) condition, the safety factor of the landslide is found to be 0.91.The value shows that when facing with a long heavy rain, the landslide can be further developed. It needs timely treatment. This paper presents the corresponding control and design measures. They include a) treating the landslide by reduce-loading and b) installing pre-stressed anchor piles in the platform level position. On the basis of slope failure in the process and mechanisms qualitative analysis, this paper uses the discrete element program UDEC to carry out the numerical simulation of landslide. Anti-slide piles with prestressed cables can be effective when they are used to against the failure of the slope. In terms of the known sliding plane, the UDEC is used to simulate the excavation and support of the landslide.the comparative analysis of the landslide displacement before and after reinforcement shows that the anti-slide piles with prestressed cable are safe and effective scheme to the landslide. Comparison shows that the anti-slide pile with prestressed anchor cable has many advantages over the anti-slide pile without prestressed anchor cable. For instance, it changes the stress of the traditional anti-slide pile, changes the cantilever beam into the species simply supported beam, and changes the passive support into active support,and so on.