Abstract：Objective：To observe the clinical effect of modified Xiaochaihu tang combined with chemotherapy for breast cancer and its effect on serum tumor markers. Methods：A total of 88 cases of patients with breast cancer were selected and divided into two groups according to different drug application. The control group was given routine chemotherapy，and the study group was additionally treated with modified Xiaochaihu tang based on the treatment of the control group. Both groups were treated for 63 days. The clinical effect and the levels of serum tumor markers，T cell subsets and immunoglobulin in the two groups were compared. Results：The total effective rate and clinical benefit rate were 77.3% and 97.8% respectively in the study group， higher than those of 56.8% and 79.5% respectively in the control group(P＜0.05). After treatment， the levels of soluble E- cadherin(sEC)， insulin- like growth factor- 1(IGF- 1)， carbohydrate antigen 125(CA125)， carbohydrate antigen 153(CA153)，carcinoembryonic antigen(CEA)，CD4+，CD4+/CD8+，immunoglobulin A(IgA)，immunoglobulin G(IgG) and immunoglobulin M(IgM) in the two groups were decreased when compared with those before treatment(P＜0.05)，and CD8 + was increased(P＜0.05)， CD3 + were decreased in the study group(P＜0.05). After treatment， the levels of sEC、 IGF-1、CA125、CA153、CEA、CD3+、CD4+、CD4+/CD8+、IgA、IgG、IgM in the study group were lower than those in the control group(P＜0.05)； CD8 + were higher(P＜0.05). Conclusion： The therapy of modified Xiaochaihu tang combined with chemotherapy for patients with breast cancer can enhance the curative effect and improve the serum tumor markers.