In order to investigate the dynamic mechanical characteristic of cemented sand and gravel(CSG) material, the hysteresis effect and the damping ratio evolution law were studied under equal amplitude cyclic loading by large dynamic triaxial test. The results show that the difference of damping effect during loading and unloading can result in the strain out of sync with the stress, the strain phase is lagging or leading the stress phase in loading, while lagging behind in unloading. There is residual deformation exist in every hysteresis loop during the whole loading process, the hysteresis loops are crescent shape and unclosed in the bottom; the lagging and the residual deformation change from big to small and then become larger with the cycle number. The computing method and the evolution law of damping ratio were studied based on the characteristic of hysteresis loop and the energy principle. It is found that the damping ratio greatly depends on the residual deformation and the area of the hysteresis loop, and the evolution curves show U shape.