Abstract: By using lentinan treat 30 patients with lung cancer during a period of rest after chemotherapy, the variabilities of cellular immune and humoral immune before and after treatment were obversed. The results showed that humoral immune indexes before and after lentinan treating were insignificantly different; The percentages of natural kill cell and CD₃⁺ cell and CD₄⁺ cell were significantly increased (P＜O.05);The rate of lymphocyte transfering was increased;The percentage of CD₈⁺ cell was decreased and the ratio CD₄⁺/CD₈⁺ cell was increased. These observations suggest that lentinan have a positive rogulation effect on immune function of patients with Lung cancer.