Irradiation is extensively utilized in food processing as an effective and convenient method. At present, numerous studies have investigated the potential of irradiation to reduce food allergenicity. The objective of this study was to investigate the effects of irradiation treatment on the structure and allergenicity of liquid and solid sesame proteins. Sesame protein extracts and lyophilized powders were irradiated at doses of 0, 2.5, 5, 7.5, and 10 kGy, respectively. The effects of irradiation on sesame proteins were investigated by CD spectroscopy, fluorescence spectroscopy, indirect competitive ELISA, western blot and degranulation experiments on KU812 cells. The experimental results demonstrated that irradiation had a more pronounced effect on liquid sesame proteins. Irradiation altered the secondary structure and increased the surface hydrophobicity, with the α-helix content decreasing from 14.27% to 13.53% and the β-sheet content increasing from 33.91% to 39.53%. Additionally, protein aggregation resulted in a reduction of free sulfhydryl groups. Following irradiation, the IC50 value obtained by indirect competitive ELISA increased from 0.695 μg mL