Oil body (OB), as natural emulsifiers, play a crucial role in emulsion stability but are often damaged to varying degrees during processing. To elucidate the stabilization mechanism of peanut milk from the perspective of oil bodies, peanut kernels were subjected to mild roasting (MR, 130 °C for 30 min) and severe roasting (SR, 150 °C for 40 min) to obtain two groups of samples with different interfacial states of oil bodies. The macroscopic stability of the emulsion and the structural properties of the OB interfacial proteins were analyzed by zeta potentiometry, rheometry, fluorescence spectroscopy, infrared spectroscopy, and confocal laser scanning microscopy. The stability results showed that the delamination rate of the MR group (4.16%) was lower than that of the SR group (6.23%), and the centrifugal precipitation rate of the MR group (2.46%) was lower than that of the SR group (3.29%). The ζ-potential was -26.84 mv, the absolute value of which was significantly higher than that of the SR group (-18.30 mv). The analysis of interfacial protein structure indicated that the OB in the MR group exhibited a core-shell structure, with high interfacial protein order and an α-helix content of 17.89%, and an interfacial tension of 45.89 mN/m. In the SR group, the OB interfacial proteins underwent denaturation and aggregation, with the α-helix content decreasing to 15.56% and the interfacial tension being 47 mN/m; the interfacial protein adsorption capacity decreased from 4.83 mol·L?¹ to 2.77 mol·L?¹. The ordered structure of oil body interfacial proteins influences the stability of peanut milk by maintaining both interfacial membrane integrity and charge stability. This study provides a theoretical reference for regulating the stability of peanut milk based on OB interface modulation.