As a kind of clean and renewable energy, nuclear energy has attracted worldwide attention in the 21st century. In the process of service, the structural materials of nuclear reactors are not only irradiated by high-energy neutrons, but also affected by hydrogen and helium elements generated by transmutation reaction, which deepens the damage of the materials, leading to a short service life, and may even induce serious accidents. Therefore, under the action of hydrogen and helium, it is very important for the development of nuclear metal structural materials to study the relationship between the irradiated defects and the irradiation temperature, irradiation dose, damage ratio and other factors, as well as the generation mechanism and evolution behavior of dislocation rings, helium bubbles and cavities in materials. In this paper, combined with relevant research results at home and abroad, the hydrogen-helium behavior of typical nuclear metal structure materials during irradiation is reviewed, and the influence mechanism between hydrogen-helium elements and irradiation defects is discussed, in order to provide reference for the performance prediction and service reliability evaluation of new nuclear structural metallic materials