Abstract: This study was aimed to explore the effect of damp-heat treatment on the antigenicity of peanut globulin Ara h 3. The Ara h 3 was purified from peanut defat powder by ammonium sulfate precipitation and treated by damp-heat at different temperatures, times and concentrations, and the optimal damp-heat treatment conditions were determined by orthogonal test. Indirect ELISA was used to detect the change of Ara h 3 antigenicity after damp-heat treatment, and the effect of damp-heat treatment on the Ara h 3 was determined by measuring exogenous fluorescence, free sulfhydryl groups, and circular dichroism spectra. The experimental results showed that the damp-heat treatment could reduce the antigenicity of Ara h 3, and the antigenicity of Ara h 3 solution was minimized at 10 mg/mL and treated at 90 ℃ for 30 min. After damp-heat treatment, the fluorescence intensity and surface hydrophobicity of Ara h 3 were enhanced, and the tertiary structure changed; the content of free sulfhydryl was increased, and the spatial structure changed; the content of α-helix and β-fold decreased, irregular coil content increased, and the secondary structure changed. After damp-heat treatment, the spatial structure of Ara h 3 was changed, and some of its epitopes were destroyed or buried, reducing its antigenicity.