Abstract: To investigate the influence of irradiation damage distribution uniformity on the mechanical properties of CLF-1 steel (China Low Activation Ferrite steel-1), samples were irradiated with 3.0 MeV Fe ions (Single Energy) and a combination of 3.0, 1.5, and 0.7 MeV Fe ions (Multi-energy Superposition), both to a dose of 4.0 dpa. The microstructural evolution of irradiated samples was characterized using transmission electron microscopy (TEM). Nanoindentation was used to evaluate the hardening effects under different irradiation damage distributions. The results indicated that under single-energy irradiation, the defect density near the sample surface was lower compared to the peak damage region, and the irradiation hardening effect was more pronounced than in multi-energy irradiated samples. Data fitting using the Nix-Gao model revealed that the equivalent hardness depended on the disparity in damage between the peak damage region and the near-surface region. This disparity influenced the equivalent hardness results derived from the Nix-Gao model fitting.