Objective:To investigate “Ruai Shuhou Prescription” and its disassembled prescriptions on growth of xenotransplants in pulmonary metastasis model of mice with breast cancer,and to explore the possible mechanism  Methods:The pulmonary metastasis model of breast cancer was set up through subcutaneous injection of 4T1-luc cells in the second breast fat pad. 5 days after inoculation, Fifty mice bearing breast cancer were randomly divided into five groups (in each group there were 10 nude mice):control group,quanfang group,yiqi group,chongren group,jiedu group. Each group except the model group was treated with “Ruai Shuhou Prescription” and its disassembled prescriptions 30 days. Tumor inhibitory rate was calculated. The growth of tumor cells in the body was monitored by bioluminescent imaging system to monitor. The pulmonary metastasis was evaluated by lung metastases quantitative analysis. The expression levels of Foxp3、TGF-β,1,、CD4,+, proteins in xenografts were detected by Western blotting  Results:The tumor inhibitory and pulmonary metastasis inhibitory rates of treatment groups compared with control group,the difference is statistically significant(P,<,0.05,P,<,0.01); yiqi group and chongren group compared with quanfang group,the difference was statistically significant (P,<,0.05), while there was no statistical significance in jiedu group compared with quanfang group (P,>,0.05). The expression levels of Foxp3、TGF-β,1, were significantly reduced and the expression levels of CD4,+, were significantly increased in all treatment groups compared with control group(P,<,0.05,P,<,0.01), and there was significantly statistic difference. Compared with quanfang group,the difference of the expression of Foxp3, TGF-β,1, and CD4,+, of yiqi group and chongren group was statistically significant( P,<,0.05), and jiedu group compared with quanfang group the difference was not tatisticaly significant (P,>,0.05)  Conclusion:“Ruai Shuhou Prescription” and its disassembled prescriptions have tumor suppression and resisting tumor metastasis,and its mechanism may be related to microenvironment of Foxp3,TGF-β,1, and CD4,+,.