Abstract: The purpose of this study was to study the effect of ferulic acid quinoa starch ester on the structure and antioxidant properties of Pickering emulsion. In this study, the application of quinoa starch as raw material to prepare di-esterified quinoa starch ester. The structure and properties of starch esters with different degrees of substitution before and after ferulic acid grafting were analyzed, and the stability, particle size, Zeta potential, antioxidant properties and droplet microstructure changes of the Pickering emulsions were studied. The results showed that, after the modification of quinoa starch granules by octenyl succinic anhydride and ferulic acid, with the increasing of ferulic acid substitution degree, the size of emulsion droplets increased, Zeta potential decreased, and antioxidant properties were significantly enhanced. Confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and optical microscope revealed that the pickering emulsion were spherical and uniformly distributed. When the substitution degree of ferulic acid was 0.69%, ABTS⁺ free radical clearance rates reached to 70.77%. Compared with the emulsion without grafted ferulic acid, ABTS⁺ free radical clearance rates increased by 65.40%, and the antioxidant capacity of emulsion was significantly improved.