On the one hand, Irradiation is everywhere and irradiation effect, especially the material irradiation damage effect under strong irradiation field, is one of the key factors for the degradation and even failure of nuclear structural materials; on the other, existing nuclear energy structural materials are far from being able to meet the requirements of advanced nuclear energy systems and there is an urgent demand for new highperformance structural materials that can withstand higher temperatures, stronger irradiation fields, stronger corrosion and wear than those of traditional nuclear reactors. In principle, high-entropy alloys (HEAs) can theoretically be designed and developed to combine a variety of excellent properties, which is an important class of candidate structural materials for advanced nuclear energy systems and should be carefully studied for irradiation damage effects. This article reviews irradiation-related investigations in the field of HEAs up to now, focusing on five detailed aspects regarding irradiation hardening and embrittlement, irradiation swelling, irradiation-induced segregation and phase transformation, helium behaviour and irradiation resistance mechanisms of HEAs. In addition, computational simulations of irradiation effects, relationship between irradiation-induced chemical disorder/chemical short-range order and resultant property changes, the excellent high temperature mechanical properties, corrosion resistance and friction and wear resistance of HEAs are outlined and summarised in this review. Finally, this article points out the future research hotspots for the irradiation effects in HEAs and their possible applications. Most important of all, research ideas and experimental examples are provided for the efficient design of "high mixing entropy" irradiation-resistant materials.