Ailanthus altissima(Mill.)Swingle is a deciduous tree belonging to the Simaroubaceae family.The root and stem bark are traditional medicines for treating many diseases,such as diarrhea,dreaminess and intestinal tract bleeding.Phytochemical investigation of Ailanthus altissima(Mill.)Swingle led to the isolation of eight compounds.Chemical structures of these compounds were identified by analyzing their NMR spectroscopic data.Among them,compounds 1,4,5,6 and 8 were isolated from Ailanthus Desf.for the first time.The antioxidant activities of these compounds were determined by DPPH radical scavenging method.