Abstract: High-oleic peanut milk meets consumer demand for healthy beverages; however, its stability urgently requires improvement. High-oleic peanuts were used as raw materials to investigate the effects of ultrasonic power (30~270 W) on the physicochemical properties of high-oleic peanut milk, oil bodies, and proteins in this study. The results showed that the influence of ultrasonic on different systems presented a power-dependent effect. As ultrasonic power was 210 W, the high-oleic peanut milk was the whitest, had the highest brightness and the best dispersion stability and thermal stability. The zeta potential of high-oleic peanut oil bodies decreased and then increased (the lowest zeta potential of oil body was −17.73 mV at 90 W), while the particle size of oil bodies gradually decreased (the smallest particle sizes of oil bodies were 2.6~2.7 μm at 210 W and 270 W) as the ultrasonic power increased. With increasing the ultrasonic power, the composition of peanut proteins did not change (P>0.05), however, the protein structure gradually became looser (α-helix and β-sheet decreased, β-turn and random coil increased, intrinsic fluorescence decreased). In addition, the protein solubility (95.20%), surface hydrophobicity (BPB bound was 68.90 μg) and emulsifying properties (EAI was 9.70 m²/g, ESI was 61.40%) were the highest at 210 W ultrasonic. This study indicated that ultrasonic treatment could improve the dispersion and thermal stability of peanut milk, which was closely related to the effects of ultrasonic on oil bodies and proteins. This provides theoretical support and technical parameters for the additive-free processing of high oleic peanut milk beverages.