To investigate the clinical efficacy of chemotherapy combined with Shenmai injection in the treatment of advanced non-small cell lung cancer (NSCLC) and its effect on cellular immunity and tumor malignant degree of patients. Methods: A total number of 162 patients with NSCLC admitted in the hospital from May 2011 to February 2016, and were randomly divided into control group and observation group, with 81 cases in each group. The patients in the control group were treated with chemotherapy, while patients in the observation group were additionally treated with Shenmai Injection. The clinical efficacy of the two groups was evaluated after 6-month treatment. The levels of serum inflammatory cytokines and tumor markers were measured and compared between the two groups before and after the treatment. Changes of T lymphocyte subsets in the whole blood of the two groups were detected and compared before and after treatment. Adverse reactions during the treatment were observed. Results: After 6-month treatment, the remission rate was 79.01% in the observation group, which was significantly higher than that of 50.62% in the control group (P<0.01). The levels of serum IFN-γ, IL-2 and TNF-α in the observation group were significantly higher than those in the control group (P<0.05 or P<0.01). The levels of IL-6 and IL-10 in the observation group were significantly lower than those in the control group (P<0.05 or P<0.01). The proportion of CD4+ and CD4+/CD8+ in the control group were significantly lower (P<0.01), while the proportion of CD8+ in the observation group significantly decreased.CD4+ ratio, NK cell ratio and CD4+/CD8+ significantly increased (P<0.05 or P<0.01), and there was significant difference between the two groups after the treatment (P<0.05 or P<0.01).The levels of serum CEA, CA125, CYFRA21-1, NSE and SCC-Ag in the two groups were significantly lower and the observation group was significantly lower than the control group after the treatment (P<0.01). The incidence of nausea, vomiting, leukopenia and thrombocytopenia was significantly lower, compared with the control group (P<0.05; P<0.01). Conclusion: Chemotherapy combined with Shenmai injection may significantly regulate the serum cytokine levels in patients with advanced NSCLC, improve the cellular immune function, effectively reduce serum tumor marker level and reduce tumor malignancy. The effect is significantly better than chemotherapy and it may effectively reduce the incidence of adverse reactions with high safety.