Abstract: To improve the emulsifying properties of peanut protein, heat treatment at different temperatures range from 80 to 120 ℃) was applied, and the effects of heat treatment on the structure and emulsifying properties of peanut protein were investigated. The results indicated that heat treatment at temperatures ≥90 ℃ promoted the formation of partial high-molecular-weight aggregates in peanut protein and significantly reduced the absolute Zeta potential (ζ_min=(18.87±0.32) mV). Small-angle X-ray scattering measurements revealed that the natural globular structure of peanut protein was partially lost after heat treatment at all temperatures, with an increase in the radius of gyration (R_{g max}=(5.19±0.01)nm) and a decrease in the fractal dimension (D_{m min}=1.83±0.09). The maximum wavelength of the fluorescence emission of peanut protein showed a significant red shift (Δλ_max=10 nm) after heat treatment, and the surface hydrophobicity and molecular flexibility were significantly improved, indicating the unfolding of protein molecular structure. Notably, the emulsifying activity of peanut protein significantly increased only at 100 ℃ and 120 ℃, whereas the centrifuge stability and salt tolerance of emulsions stabilized by peanut protein significantly improved after heat treatment at all temperatures. Heat treatment enhanced the emulsifying properties of peanut protein by changing its molecular structure, thereby broadening the application range of peanut protein.