Abstract: The interface of soil and structure exists widely in geotechnical engineering, and it is essential to establish a constitutive model that can describe the deformation properties of interface reasonably. In this study, direct shear tests on the interface of ‘Nuozhadu filter material-concrete baseplate’ were conducted and then simulated using the finite element method (FEM) to analyze the properties of shear deformation and progressive failure of the interface. Results show that the failure of soil-structure interface, which is significantly different from that of a soil or structure element, manifests a progressive process. The measured displacement in the test consists of two parts, i.e., the shear displacement at the interface and the deformation of the soil adjacent to the interface. In FEM analyses, the former can be simulated appropriately by a perfectly plastic model, and the latter by conventional constitutive models of soil.