Effects of cultivation methods on quality characteristics, pasting characteristics, chemical components, and antioxidant activities of sweet potatoes (Ipomoea batatas (L.) Lam) were determined. The Brix degree, hunter color value, pasting characteristics, moisture, protein, and mineral contents of the sweet potatoes showed significant differences from cultivation methods. The total polyphenol and flavonoid contents of the methanolic extracts of the sweet potato’s pericarp were higher than sweet potato’s sarcocarp. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of the sweet potato’s pericarp on the conventional culture and successful cropped hairy vetch culture was 776.38 and 715.20 ㎎ TE/100 g sample. The 2,2’-azino-bis-3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS) radical scavenging activity of the sweet potato’s pericarp on the conventional culture and successful cropped hairy vetch culture was 708.03 and 708.58 ㎎ TE/100 g sample. Generally, there was a difference in antioxidant compound content and radical scavenging activity on the methanolic extract of sweet potato with cultivation methods.