Objective:Based on the basic TCM theory of the lung and the large intestine being interior-exteriorly related,this experiment explores the effect of Chinese herbal medicine－Jianpi Guchang recipe(JPGCR)on improving intestinal immune barrier function,regulating the balance of intestinal Treg/th17 cells and inhibiting the invasion and metastasis of lung cancer in mice after chemotherapy by mediating intestinal flora. MethodsLewis lung cancer cells were subcutaneously inoculated into C57BL/6 male mice to establish lung cancer model mice. Then according to the random number table,eighteen successful modeling mice were divided into tumor bearing group, chemotherapy group and Chinese medicine group with 6 mice in each group. After modeling,intervention was carried out. Cisplatin(density-dependent phosphoprotein, DDP) solution(0.1 mg/d) was injected intraperitoneally for 3 days in the chemotherapy group and traditional Chinese medicine group,and same volume of saline was injected intraperitoneally for 3 days in the tumor-bearing group. From the first day,the traditional Chinese medicine group was given JPGCR 0.6 mL/d by gavage. The Tumor bearing group and chemotherapy group were given same volume of saline daily. Samples were taken from the 18 mice after 21 days of intervention. The body weight, tumor weight, number of lung metastases in the three groups of mice were taken. Intestinal flora of mice was measured by Illumina Genome Analyzer IIx,and the levels of Th17 and Treg cell-related transcription factor RORγt and Foxp3 in small intestinal lymphoid tissue of mice were analyzed by RT-PCR.  Results:The general condition and body weight of mice in the JPGCR group were better than those of the chemotherapy group,and the difference was statistically significant(P<0.01). The anti-tumor rate and inhibition rate of lung metastasis of mice in the JPGCR group were better than those in the chemotherapy group(P<0.05). Compared with the chemotherapy group,the intestinal flora diversity index Chao1 and Shannon of mice in the JPGCR group were increased significantly(P<0.01). Compared with the chemotherapy group,the intestinal immune index FoxP3 and RORγt of mice in the JPGCR group were decreased significantly(P<0.05).  Conclusion:JPGCR can inhibit the invasion and metastasis of lung cancer cells in mice by increasing the diversity of intestinal flora,improving intestinal flora,regulating the balance of Th17/Treg cells in intestine of lung cancer mice,maintaining the balance of intestinal immunity and improving the body immunity.