Objective：To observe the clinical effect of Kang'ai Shengsui decoction for the preve ntion and treatment of myelosuppression after the chemotherapy in intermediate and advanced non-small cell lung cancer.Methods：Divided 104 cases of patients with intermediate and advanced non-small cell lung cancer into the control group and the observation group randomly，with 52 cases in each group.Both groups were given TP regimen intervention，and if myelosuppression occurred during the chemotherapy，the control group would be given subcutaneous injection of recombinant human granulocyte colony-stimulating factor， while the observation group was additionally given Kang'ai Shengsui decoction， 21 days constituting one therapeutic course，and both groups were continuously treated for three courses.Observed the occurrence of myelosuppression in patients，detected the levels of CD4+and CD8+，immunoglobulin，natural killer(NK)cells，white blood cell count(WBC)， hemoglobin(Hb)， and platelet(BPC)in T lymphocyte subsets before and after chemotherapy and recorded the occurrence of adverse reactions during the treatment.Results：The incidence of myelosuppression in the observation group and the control group was 13.46% and 46.15% respectively and the incidence of myelosuppression in the observation group was lower than that in the control group(P ＜ 0.05).After treatment，the levels of Tlymphocyte CD4+，CD4+/CD8+，IgA，IgG，IgM and NK cells in the two groups were all increased when compared with those before treatment and the levels of CD8+were decreased when compared with those before treatment，differences being significant(P ＜ 0.05).Compared with those in the control group，six indexes mentioned above in the observation group were increased/decreased more obviously after treatment(P＜ 0.05).After treatment，the contents of WBC，Hb and BPC in the two groups were all decreased when compared with those before treatment(P＜ 0.05).Compared the two groups after treatment，the contents of WBC，Hb and BPC in the observation group were all higher than those in the control group(P＜0.05).The incidence of adverse reactions in the observation group and the control group was 11.54% and 30.77% respectively and the incidence of adverse reactions in the observation group was lower than that in the control group(P＜0.05).Conclusion：The application of Kang'ai Shengsui decoction can reduce the incidence of myelosuppression after the chemotherapy in intermediate and advanced non-small cell lung cancer，enhance the immune function of patients，and relieve the adverse reactions.