Objective To explore the impact of chemotherapy on peripheral Th1 and Th2 cytokines in patients with non-small cell lung cancer.Methods The expression of Th1 and Th2 cytokines before chemotherapy 、after three cycles and six cycles in non-small cell lung cancer was detected by enzyme linked immunosorbent assay.Results The expressions of IL-2 and IFN-γ of advanced non-small cell lung cancer were lower than those of normal control group(P0.05).The levels of IL-6 and IL-10 were higher than those of normal control group(P0.05).The expressions of IL-2 and IFN-γ of advanced non-small cell lung cancer after three cycles chemotherapy were higher than those before chemotherapy(P0.05).The levels of IL-6 and IL-10 after three cycles chemotherapy were lower than those before chemotherapy(P0.05).The expressions of IL-2 and IFN-γ of advanced non-small cell lung cancer after six cycles chemotherapy were lower than those after three cycles(P0.05),but IL-6 and IL-10 were slightly lower than those after three cycles chemotherapy(P0.05).Conclusion There is immune related factor disorders in Patients with advanced non-small cell lung cancer.The immunity state can be improved after three cycles chemotherapy,but can't be improved further even become worse after 6 cycles.