Abstract: It is important to consider the small-strain stiffness of soil in analyzing the interaction between soil and structures. The attenuation rate of soil stiffness should be determined through advanced triaxial test with local strain measurement device, which restricts the application of small strain model. Although systematic study of typical soils has been carried out abroad through such experiments, it is rarely reported in China. This paper proposes an elasto-plastic constitutive model with sine function and hyperbolic function to simulate the stress-strain relations during loading and unloading respectively. The calculated results using the proposed model for a variety of soils are compared with experimental data and good agreement is found, which proves the model is reasonable.