This paper takes the developed landslide in Langao County of Shaanxi Province as the research object with the help of geotechnical experiments,physical simulation and numerical simulation,reveals the deformation and infiltration law of landslide under rainfall conditions,and studies the deformation and failure characteristics and formation mechanism of rainfall-induced accumulation landslide. The physical model test shows that:The relationship between seepage rate and time is exponential,and the relationship is y=6.658 83x^{-0.900 34};With the rainfall and changes of groundwater level,the accumulation of landslides is mainly characterized by traction whose development process can be summarized as follows:the generation of cracks→ the expansion of cracks→ the penetration of cracks→ secondary sliding→ overall sliding five stages;It is found that the binary structure of the landslide is the decisive factor in the formation of the landslide. The rainfall infiltration leads to the enrichment of the water flow near the bedrock surface,which is an important predisposing factor for the landslide.Numerical simulation results show that the slope stability decreases with the duration of groundwater,and the shear strain and the slope deformation increase gradually.