Abstract: The optimization of extraction technology of soluble dietary fiber (SDF) in sunflower seed shells and its anti-oxidative activities were studied. Results showed that the optimized extraction conditions were as follows:solid-liquid ratio 1∶30, extraction solvent 9.5% Na OH, extraction temperature 40℃, extraction time 30 min. Under these conditions, the extraction rate of SDF was 21.32%. The SDF showed strong scavenging activities on1, 1-Diphenyl-2-picrylhydrazyl radical (DPPH) , superoxide radical (O2-·) and hydroxyl radical (·OH) methods, the scavenging rates for the radicals were 86.67%, 70.32% and76.33%, respectively, when the concentration was 1.0mg/m L.