Based on the project of GRS-IBS in Taihang No.1 Tourism Road K43+175 in Shanxi Province, a series of dynamic triaxial tests of reinforced sand with different reinforcement spacings were carried out. To provide reference for deformation prediction and condition evaluation during design process of GRS-IBS, the influence of the reinforcement spacing on the dynamic response characteristics such as dynamic strength, dynamic shear modulus, damping ratio and cumulative plastic strain were analyzed respectively. The evolution patterns of dynamic response characteristics were also discussed. The results show that the type of dynamic stress-strain curve changes from hyperbolic to linear with the increase of the number of reinforced layers, and the peak as well as dynamic strength and dynamic modulus are also improved; the denser the reinforcement, the greater the increase would be. Increasing the confining pressure or the number of reinforced layers can reduce both the dynamic shear strain and the damping ratio but increase the dynamic shear modulus. The axial plastic strain can be inhibited effectively by increasing the number of reinforcement layers under the cyclic loading, so that the reinforcement spacing in GRS-IBS structure should be controlled to raise the cyclic stress ratio and maintain the long-term dynamic stability of the reinforced soil.