As an environmentally friendly pesticide formulation, oil-base suspension concentrate has been rapidly developed in recent years. However, due to the relatively weak research on the stability mechanism and the relative lack of precise, quantitative and microscopic characterization methods, the oil-base suspension concentrate products are prone to oil stratification, flocculation, paste and agglomeration during production and storage. As an important surface analysis technology, XPS has the characteristics of high sensitivity, simple sample preparation and small sample destructiveness. It’s often used for qualitative and quantitative analysis of solid surface elements and atomic valence analysis, which is very suitable for dispersant adsorption performance and stability mechanism research. In this research, XPS, FITR and SEM were used to study the adsorption performance of oil phase dispersant containing polyamine anchoring group onto the surface of oxadiargyl particles in oil phase from the microscopic view, which provided a theoretical basis for the application of the dispersant in the oil-based suspension concentrate of pesticide.The results showed: after the dispersant was adsorbed, the Cl, N, O electron peak intensity at the interface of oxadiargyl was weakened, and the C electron peak intensity was enhanced, indicating that the dispersant formed good adsorption on the surface of oxadiargyl. The thickness of the adsorbed layer of the dispersant on the surface of oxadiargyl was calculated to be 6.746 nm using the Cl element as a characteristic element. There was no new absorption peak in the infrared spectrum of oxadiargyl after the adsorption of the oil-base dispersant containing polyamine anchoring group, which indicated that the adsorption between the dispersant and oxadiargyl was physical adsorption with van der Waals force as the main binding force. From the micromorphology of the sample before and after adsorption, it was showed that the surface of the oxadiargyl particles before absorbing the dispersant was rough and had a lamellar structure, while the surface became smooth and the layered structure disappeared after absorbing the dispersant. The difference illustrated that the dispersant containing polyamine anchoring groups formed a coating on the surface of oxadiargyl and improved the physical stability of oxadiargyl oil-base suspension concentrate by providing steric hindrance through the non-polar solvated chains.