Abstract: OBJECTIVE To research scavenging effect on the oxygen free radicals in different extracts from Omanthus fragrans. METHODS Different polar extracts in Omanthus fragrans were obtained by different solvents such as water, petroleum ether, ethyl acetate and n-butanol. 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and superoxide anion free radical(O₂^-) produced in lactoflavin illumination system were measured by electron spin resonance(ESR) and spin trapping technology. The scavenging effects of different extracts from Osmanthus fragrans were on the DPPH free radical and superoxide anion free radical(O₂^-). RESULTS Based on vitamin C (VC) as a contrast control, aqueous layer, petroleum ether layer, ethyl acetate layer, n-butanol layer and VC whose capacities of DPPH scavenging IC50 (μg·mL^-1) were 59.63, 53.93, 28.33, 38.89, 40.93 μg·mL^-1 in turn; capacities of superoxide anion free radical(O₂^-) scavenging and VC IC50 (μg·mL^-1) were 63.37, 55.47, 30.20, 48.36, 41.52 μg·mL-1 in turn. Among them, capacities of DPPH scavenging and superoxide anion free radical(O₂^-) scavenging from ethyl acetate layer were maximum. CONCLUSION By comparison with capacities of DPPH scavenging and superoxide anion free radical(O₂^-) scavenging, the situation of distribution in each phase was known about antioxidant constituents from Osmanthus fragrans. According to the result, antioxidant constituents were isolated purposively.