Objective: To study the influence of Huaier granule adjuvant therapy on immune function and postoperative survival status in patients with triple negative breast cancer (TNBC) after modified radical mastectomy. Methods: Ninety-five TNBC patients undergoing adjuvant chemotherapy after modified radical mastectomy were divided into observational group (56 cases) and control group (39 cases). Patients in the observational group received oral administration of Huaier granule during and after chemotherapy and radiotherapy (20 g, 3 times daily for 1.5 years), while those in the control group did not receive any traditional Chinese medicine preparations during adjuvant therapy. The quality of life, disease free survival (DFS) during treatment and follow-up period and serum T cell subset composition at 3, 6, 12 and 24 months after surgery between the two groups were compared. Results: In observational group compared with control group, the improvement rate of Karnofsky score was significantly increased and DFS was significantly prolonged (all P<0.05). There was no significant difference in the percentage of CD3+ cells between the two groups at any time points after surgery (all P>0.05), but the percentages of CD4+ and NK cells and CD4+/CD8+ ratio in observational group were all significantly higher than those in control group at each time point (all P<0.05). Compared with their preoperative value, in observational group, the percentage of CD3+ cells at 3 months after surgery of treatment was significantly decreased (P<0.05), but began to return to normal 6 months later (all P>0.05), and the percentages of CD4+ and NK cells and CD4+/CD8+ ratio were significantly increased during 6 to 24 months after surgery (all P<0.05); in the control group, the percentages of CD3+ cells were significantly reduced during 3 to 6 months after surgery (all P<0.05), and began to recover 12 months later (all P>0.05), and the percentage of CD4+ cells and CD4+/CD8+ ratio were significantly lowered during 3 to 12 months after surgery (all P<0.05). Conclusion: For TNBC patients, Huaier granule administration during postoperative adjuvant therapy may help improve the immune function, increase quality of life and prolong the DFS.