To evaluate the effect of Xiaochaihu Decoction combined with chemotherapy on breast cancer and to observe its effects on immune function. Methods:A total of 60 cases with advanced breast cancer were included in the study. The patients were divided into control group and observation group. 32 cases in control group received intravenous chemotherapy, and 28 cases in the observation group received intravenous chemotherapy drug treatment and oral administration of Xiaochaihu Decoction. The treatment period was 3 months. Symptoms in two groups before and after treatment, the scores of quality of life, improvement rate of tumor markers (CEA, CA153, CA125), the content changes of immune indexes (CD3+, CD4+, CD8+, CD4+/CD8+, IgG, IgA, IgM) change rate and adverse reaction were compared. Results:Quality of life scores improved in the two groups of patients after treatment, and the observation group was better than the control group (P<0.05); the total efficiency of observation group was 60.71%, and had significant difference when compared with 31.25% in the control group (P<0.05); after treatment, CEA, CA153, CA125 concentrations of two groups were significantly decreased, and there was statistically significant (P<0.05) compared with before treatment. The observation group was better than the control group (P<0.05); after treatment, peripheral blood CD3+, CD4+, CD4+/CD8+, IgG, IgA and IgM levels of the observation group were higher than the control group, and CD8+ level was lower than the control group. The differences were statistically significant (P<0.05); The adverse reactions were nausea and vomiting, headache and dizziness, renal damage, leukopenia, alopecia and cardiac toxicity, and the adverse reaction rate of the observation group was lower than in the control group. The difference was statistically significant (P<0.05). Conclusion:Xiaochaihu Decoction can improve the clinical curative effect and optimize the quality of life by enhancing the immune ability of the breast cancer patients.