It is a challenge work for existing simulations to describe the complex multi-scale behaviors of radiation damages in nuclear materials. By employing of atomistic models as well as developing of the Monte Carlo model for ion irradiation and the cluster dynamics model for defect evolution, we developed a multi-scale modeling scheme to study the micromechanics in processes from primary damages to long-term evolution of defects, which provides a general way for analyzing of irradiation-induced phenomena in nuclear materials.