Acanthopanax senticosus is a typical oriental folk medicinal herb and has been used clinically as a tonic, anti-rheumatic and prophylactic for chronic bronchitis, hypertension, anti-stress, ischemic heart disease, and gastric ulcer. Acanthopanax senticosus was successively extracted with water, boiling water, methanol, and 70% methanol. The antioxidant properties of various extracts were evaluated by antioxidant tests, such as DPPH free radical-scavenging activity, metal-chelating activity, superoxide radical scavenging activity, and reducing power assay. The boiling water extract exhibited the highest activity in the in vitro models of DPPH free radical-scavenging activity, and reducing power assay. The 70% methanol extract showed high metal chelating activity. In addition, the total phenolic content of different extracts was also investigated. These results indicate the high possibility of using A. senticosus for medical application due to their efficient antioxidant properties.