Objective:To observe the clinical efficacy of Sanqi Decoction in the prevention and treatment of myelosuppression induced by chemotherapy in non-small cell lung cancer with syndrome of qi and yin deficiency. Methods60 patients of non-small cell lung cancer with syndrome of qi and yin deficiency were randomly divided into the treatment group and control group,30 case in each group. The control group was treated with platinum chemotherapy,and the treatment group was treated with Sanqi Decoction additionally based on chemotherapy. The chemotherapy course of both groups were 6 weeks,and Sanqi Decoction was given one week in advance(a course of 7 weeks in the treatment group).The incidence and classification of myelosuppression were observed,and the serum level of granulocyte macrophage colony stimulating factor (GM-CSF) and Karnofsky performance scores(KPS)were compared.  Results:①The incidence rate of myelosuppression in the treatment group was significantly lower than that in the control group(P<0.05).The incidence rates of toxic reaction with I,II degree on white blood cell (WBC),red blood cell (RBC),platelet (PLT) and neutrophil(NEUT) were significantly lower than those in the control group(P<0.05). ②After treatment,the level of GM-CSF in the treatment group was significantly higher than that in the control group(P<0.05). ③After treatment,the improvement and stability of KPS in the treatment group were significantly better than those in the control group(P<0.05).  Conclusion:Sanqi Decoction shows significant efficacy in the prevention and treatment of myelosuppression induced by chemotherapy in non-small cell lung cancer with syndrome of qi and yin deficiency,which can regulate the related cytokine concentration and improve the life quality of patients.