Abstract: Nanored elemental selenium is a kind of nanograin,its diameter is between 20nm-60nm.Using the planted Lewis Lung Cancer(LLC)model,its anti-cancer function w as studied.The result revealed that:Mice were inigated with nano red elermental selenium for IO days,the dose was 2mg/kg·bw,4 mg/kg·bw,8 mg/kg·bw.Compared with control group,nanored elemental selenium in three dose all could significantly inhibit tumor volume and tumor weight;Mice were separ atelyinig ated with nanored elemental selenium in dose of 8mg/kg·bw and cyclophosphamide in dose of 20 g/kg·bw for 10 days.Compared with control group,the nanored elemental selenium and cyclophosphamide all could inhibit the tumor volume,the tumor weight,the indexes of tumor metastases in lung,and extend life of micesignificantly.The result showed that nanored elemental selenium could inhibit the planted Lewis Lung Cancer.