〔Abstract〕Objective To investigate the effects of sevoflurane combined with dexmedetomidine on immune function and hemodynamics of patients undergoing radical mastectomy under general anesthesia for breast cancer. Methods A total of 100 female breast cancer patients admitted to the First Affiliated Hospital of Nanyang Medical College from October 2019 to March 2021 were selected, and they were divided into observation group and control group according to different medication regimens, with 50 patients in each group. The control group received dexmedetomidine general anesthesia maintenance and the observation group received sevoflurane combined with dexmedetomidine general anesthesia maintenance. Immunoglobulin G (IgG), differentiation cluster 3+ (CD3+ ), CD4+ , CD8+ , CD4+ /CD8+ , nitric oxide (NO), systolic blood pressure (SBP), adrenocorticotropic hormone (ACTH), mean arterial pressure (MAP), heart rate (HR) and blood oxygen saturation (SaO2) were compared between the two groups. Results There were no significant differences in the levels of IgG、ACTH、CD8+、NO、CD3+、and the ratio of CD4+ /CD8+ between the two groups before surgery, and the differences were statistically significant (P > 0.05). Three days after operation, the levels of IgG, CD8+ , CD3+ , and the ratio of CD4+ /CD8+ in the observation group were higher than those in the control group, the differences were statistically significant (P < 0.05). The levels of ACTH and NO were lower than those in the control group, and the differences were statistically significant (P < 0.05). There were no significant differences in SBP, HR, MAP and SaO2 between the two groups before anesthesia induction (P > 0.05). SaO2 and MAP in the observation group were higher than those in the control group 1 min after anesthesia maintenance, and the differences were statistically significant (P < 0.05). SBP, HR, SaO2 and MAP of the observation group were higher than those of the control group 30 min after anesthesia maintenance, and the differences were statistically significant (P < 0.05). Conclusion Sevoflurane combined with dexmedetomidine in general anesthesia during radical mastectomy for breast cancer has a good and accurate effect on anesthesia maintenance, which can effectively maintain the intraoperative circulation stability of patients, reduce surgical stress and the impact of surgery on the immune function of patients.