Abstract: As one of the core components in wind-to-electric energy conversion systems, wind turbine generators are rapidly expanding in global deployment. However, the blade icing, a phenomenon that severely compromises operational efficiency, has emerged as a critical challenge for the industry, consequently drawing widespread attention. With the growing demand for wind energy, turbine sizes have increased significantly, yet research on full-scale turbine icing characteristics and anti-icing strategies remains limited. Therefore, this study employs numerical simulations to systematically investigate icing accretion patterns on a three-dimensional, large-scale wind turbine with a 200 m rotor diameter. Simulation results are compared against natural icing data to assess the aerodynamic impact of icing, determine the anti-icing zones and possible strategies. Results indicate that the ice accretion predominantly occurs along the leading edge, and minor ice accretion can also be observed at the tip’s trailing edge due to local airfoil geometry. The maximum ice thickness decreases monotonically from the blade tip toward the root, attaining comparable values at radial positions below 40% (r/R≤40%) under all tested icing conditions. Based on these accretion patterns, we identify the critical anti-icing zone as s/c_\rm local ≤0.25 of the chord length and determine the required heat-flux-density distribution at various icing temperatures. These findings provide quantitative guidelines for designing more efficient thermal anti-icing systems in future large‐scale wind turbines. The results show that the closer the heating zone is to the blade tip, the higher the required heat flux density. For the same heating zone, the greater the temperature difference between the anti-icing temperature and the icing temperature, the higher the required heat flux density.