Abstract: Objective: To study the influence of Taihe Cedar aqueous extract on Caenorhabditis elegans( C.Elegans)biological characteristics and the scavenging free radicals ability in the body of the water extract clear nematodes.Methods: The length,life span,activity and content of oxygen free radicals of nematodes which cutlured by NGM culture medium with three different concentration of the Taihe cedar aqueous extract were measured to investigated the effect of Taihe Cedar aqueous extract on the biological characteristics and the antioxidant ability of nematodes.Results: Compared with control,significant differences were observed on the average length,longevity,activity times per minute and the content of oxygen free radicals of nematodes cultured with concentration of0.5 mg/m L cedar aqueous extract( p < 0.01).The experimental results showed that the concentration of Taihe Cedar water extract could promote the growth of C. Elegans,and possess obvious effect of scavenging free radicals.