the deep-frying procedure of caijiao in sunflower oil (sfo) needs natural antioxidants. in the present study, the essential oil of coriandrum sativum (cseo) was added into sfo at 0.16 g/kg to prepare sfo sample. during the deep-frying procedure of caijiao, total polar compounds (tpc), thiobarbituric acid (tba), conjugated dienes (cd), conjugated trienes (ct), polymers, viscosity and b* were prominently inhibited, together with the obvious reduction of l* (p < 0.01 or p < 0.05). the sensory attributes of caijiao were also obviously improved (p < 0.01 or p < 0.05). in the meantime, the addition of synthetic antioxidants to sfo, such as tbhq, bha and bht, didn<apos;>t display effective antioxidant effect. after the bioassay-guided fractionation, the antioxidant effect of cseo was attributed to one of its natural products, eugenol. the research and development of eugenol for effective natural antioxidants is of much importance for the whole food industry.