Abstract: Irradiation hardening is one of the most common effects in irradiated metallic material. Investigations on irradiation hardening mechanisms are of great significance to design reliable structural materials for nuclear reactors. Irradiation induced defects act as obstacles to dislocation motion which is believed as the main reason for irradiation hardening. In recent years, the rapid development of dislocation dynamics simulation method built a bridge connecting the microstructure and the macroscopic mechanical properties and widely applied to investigate the mechanisms of irradiation hardening. For some irradiation defects such as dislocation loop and stacking fault tetrahedron, dislocation dynamics simulation is capable of capturing their influences on the evolution of dislocation network and the macroscopic mechanical response, making it possible for quantitative prediction of the irradiation hardening. In this paper, the progress of dislocation dynamics simulation on irradiation hardening was reviewed from three aspects: The basic dislocation dynamics model, the recent dislocation dynamics simulations on typical irradiation defects induced hardening and the development of the theoretical models of irradiation hardening. Some scientific problems for future research were also presented.