Abstract: the determination of residual strength of sliding belt is a very important for analysis of reactivated landslides. The silty sand(SM) is the erratic soil which behaves complex shear behavior. This study investigated the influence of over-consolidation ratio(OCR)on the shear strength of SM type landslide soil using the multistage ring shear test under different pre-consolidation pressure. A series of ring shear tests were conducted to measure the drained residual strength under OCrs of 1~12 at shear rates of 0.06mmmin-1.The test results showed that peak strength of SM type landslide soil increased linearly with increasing OCrs under the same normal stress during shearing, but residual strength of SM type landslide soil was not affected significantly by the over-consolidation process.