Abstract: OBJECTIVE To investigate the effects of dexmedetomidine on immune regulation in patients with sepsis. METHODS A total of 82 patients with sepsis admitted to our hospital from Jun. 2015 to May 2016 in the emergency intensive care unit (EICU) were selected as the subjects of this study, and were randomly divided into experimental group and control group, with 41 cases in each group. The experimental group was treated with dexmedetomidin, and the control group was treated with midazolam. The APACHEⅡ scores before and after treatment between the two groups were observed. The changes of T lymphocyte counts in the peripheral blood, plasma interleukin-1 (IL-1), IL-6, IL-10 and tumor necrosis factor-α (TNF-α) of the two groups before and after 7 days of the treatment were investigated. RESULTS After treatment, the APACHEⅡ scores of both groups decreased to some extent. The APACHEⅡ score of the experimental group was (12.56±2.44) points, which was significantly lower than (17.95±3.62)points of the control group(P=0.037). After 7 days of treatment, the levels of CD₃⁺, CD₄⁺, CD₈⁺, and CD₄⁺/CD₈⁺ in the experimental group were (67.25±13.64)%, (40.36±6.27)%, (39.13±7.46)%, and (1.54±0.38)%, which were significantly higher than those in the control group (P＜0.05). After treatment, IL-1 and IL-6 in the experimental group were (9.84±1.48) ng/L and (24.53±5.95) ng/L, which were significantly lower than those in the control group(P=0.032, 0.046). The IL-10 level was (74.32±8.32) pg/ml, which was significantly higher than the control group (P=0.043), but the TNF-α level in the experimental group was (0.71±0.09)μg/L, which was lower than that in the control group, but the difference was not significant (P=0.076). CONCLUSION Dexmedetomidine has analgesic and sedative effects, and can effectively improve the immune function of patients with sepsis, reduce inflammatory response, which is beneficial to the prognosis of patients.