Agrimonia pilosa Ledeb is used as the tonic for asthenia and fatigue in China. Considering that the energizing effect might be correlated with antioxidant properties, we investigated the antioxidant activities of aqueous extract (AE) from Agrimonia pilosa Ledeb by assessing radical-scavenging and anti-lipid-peroxidation abilities. We found that AE shows a moderate antioxidant activity to scavenge DPPH*, O2(-)* and *OH and inhibit beta-carotene bleaching with IC(50) values of 13.0, 33.2, 351, and 11.9 microg/ml, respectively, while its AcOEt-soluble fraction (ESF) and BuOH soluble fraction (BSF) exhibit remarkable efficiencies. The ESF's IC(50) values of scavenging DPPH*, O2(-)*, and *OH, and inhibiting beta-carotene bleaching are 5.6, 5.8, 171, and 7.6 mircog/ml, respectively, and those of BSF are 7.5, 8.4, 82.0, and 6.2 microg/ml, respectively. In addition, we found that there is a significant correlation between total phenol content and the antioxidant activity determined by O2(-)* and *OH scavenging, and beta-carotene-bleaching assays. Furthermore, HPLC analysis revealed the presence of quercetin, hyperoside, quercitrin, taxifoliol, luteolin-7-O-beta-D-glucopyranoside, and rutin in Agrimonia pilosa Ledeb. Thus, we suggest that the extracts from Agrimonia pilosa Ledeb, could be considered as natural antioxidant sources and dietary nutritional supplements to prevent oxidation-related diseases.