Dynamic properties of the soil such as shear modulus and damping ratio are important parameters in the prediction of the dynamic response of geotechnical engineering structures. Though these properties are dependent on several factors, strain amplitude and confining pressure have a major effect. Liquefaction is another important phenomenon associated with the undrained response of granular materials in loose state. In this paper, the results of the numerical simulation of cyclic triaxial shear tests on three-dimensional assembly consisting of 1000 sphere particles using Discrete Element Method (DEM) have been reported under undrained conditions. From the results, the shear modulus and damping ratio have been estimated for a range of shear strain and confining pressure. The DEM simulations have modeled the liquefaction behaviour under undrained conditions very close to the real experimental behaviour.