Objective To observe the antitumor activity of sedum lineare thunb(SLT) and it′s affection on antioxidation and tumor immunology in S180‐bearing mice .Methods S180‐bearing mice model were established by subcutaneously inoculating S180 ascitic tumor into the right armpit .From the second day ,the mice were treated with normal saline ,cyclophosphamide (50 g/kg) or two doses of SLT (4 ,8 g/kg) through intragastric administration ,and the process extent 14 d .After the last administration ,the mice body weight and the index of tumor ,spleen and thymus were calculated ,classification of white blood cells in peripheral blood was tested ,and the activity of SOD and GSH‐Px as well as the content of MDA and NO in serum were measured .Results The body weight of mice treatmented with SLT was dramaticlly higher than those of the CTX (P< 0 .05) .Compare with the model group ,SLT groups showed decreases in tumors index (P<0 .05) ,spleen index (P<0 .05) ,percentage of peripheral blood neutro‐phil (P<0 .05) and monocyte (P<0 .05) ,and increases in thymus index (P<0 .05) and percentage of lymphocyte (P< 0 .05) . The activity of SOD and GSH‐Px and NO level in the SLT groups mice′s serum were significantly higher than those of the model group (P<0 .05) ,while the content of MDA in the SLT groups mice′s serum was markedly lower than those of the model and CTX groups(P<0 .05) .Conclusion SLT has antitumor activity in S180‐bearing mice bysuppressing oxidative stress and modula‐ting tumor immune .