The most important parameters in evaluation of dynamic behavior of soil structures such as highways, retaining walls, and embankments are shear modulus and damping ratio. A fiber reinforced soil behaves as a composite material in which fibers of relatively high tensile strength are embedded in a matrix of soil. Shear stresses in the soil mobilize tensile resistance in the fibers, which in turn imparts greater strength to the soil. This study deals with assessment of fine sand reinforced with carpet and geotextile strips when subjected to dynamic loading by performing two sets of cyclic triaxial test- large scale and small scale. In these tests the influences of various parameters such as confining pressure, mixture ratio, and the ratio of strip length to its thickness which will herein be referred to as aspect ratio on the dynamic behavior of reinforced fine sand were studied. The results demonstrate that the effects of this kind of reinforcement on shear modulus in low confining pressures (less than 100kPa) are negligible and in high confining pressures are considerable.