In the process of finding antioxidants from native plants in Korea, the ethyl acetate fraction of Cyperus sanguinolentus Vahl (Cyperaceae) methanol extract was observed to have a strong scavenging effect on DPPH radicals. Superoxide dismutase (SOD), catalase, and oxidative stress resistance were measured using model system in combination with reactive oxygen species (ROS) levels in the ethyl acetate fraction of Cyperus sanguinolentus (EACS). In addition, to determine whether EACS-treated C. elegans produced resistance proteins to oxidative stress, we checked SOD-3 expression using transformant strain CF1553. As a result, the EACS increased SOD and catalase activity and reduced ROS accumulation in a dose-dependent manner. And, the CF1553 nematodes treated with EACS showed higher SOD-3::GFP intensity than the control group.