In order to investigate the antioxidant capacity of sedum (dolnamul, Sedum sarmentosum) and to offer a scientific basis for the medicinal use of it, lyophilized sedum leaves were extracted with n-hexane, n-butanol, ethyl acetate, and methanol, respectively. The methanol extract (ME) showed the highest extraction yield, but no significant differences in the extraction yield were observed. The total polyphenol content (TPC) of the ethyl acetate extract (EAE) and the ME was significantly higher than that of the non-polar solvent extracts. The EAE and ME showed the superior antioxidant activities in the DPPH, oxygen radical absorbance capacity (ORAC), and ferric reducing ability of plasma (FRAP) assays. Lipid peroxidation was efficiently inhibited by the addition of the sedum extracts in the ferric thiocyanate (FTC) and thiobarbituric acid reactive substances (TBARS) assays, but significant differences among the tested extracts were not observed. The ME showed the potent lipid peroxidation inhibitory activity comparable to butylated hydroxytoluene (BHT). The correlations between the TPC and the antioxidant activities based on the DPPH, ORAC, and FRAP assays were highly positive ($R^2$>0.899).