In recent years, various studies have been undertaken on how to use waste materials in Civil Engineering projects. Among waste materials, waste rubber has been highlighted to be used for different purposes such as reinforcing of soil and making of reinforced slopes. To investigate the properties of granulated rubber-soil mixture and its application in making of slopes behind retaining walls, some series of cyclic tri-axial tests and numerical analyses were carried out. In the former, dynamic properties of granulated rubber-soil mixture such as shear modulus and dynamic behavior were obtained and in the latter the effect of using granulated rubber-soil mixture on dynamic pressures and displacement of retaining walls during earthquake was investigated. The results of the present study showed that for all the confining pressures, with an increase in rubber percentage, shear modulus decreases while for any percentage of rubber inclusion, shear modulus increases as the confining pressure increases. In addition, new relations were introduced to define maximum shear modulus (Gmax) and Normalized shear modulus as functions of confining pressure and granulated rubber percentage. Regarding the dynamic analyses of the retaining wall, with an increase in rubber percentage, a decrease in dynamic pressure and residual displacement was observed.