Abstract: Objective To investigate the expression of T cell immunoglobulin and mucin domain-containing protein 3 (Tim-3) on the surface of T cells in patients with brucellosis (Bm), as well as the expression of interleukin-10 (IL-10) and transforming growth factor beta (TGF-β) in serum, and to analyze the differential expression of these indicators in patients with acute and chronic brucellosis, in order to provide new approaches for the differential diagnosis of acute and chronic brucellosis. Methods A total of 56 patients diagnosed with brucellosis at the First Affiliated Hospital of Xinjiang Medical University from April 2023 to September 2023 were selected, including 31 patients in the acute phase and 25 patients in the chronic phase. Additionally, 35 healthy individuals underwent routine physical examinations within the same period served as healthy controls. Flow cytometry was used to detect and compare Tim-3 levels on the CD4+ T cells' surface among the groups. Levels of serum IL-10 and TGF-β were measured and compared using CBA and ELISA, respectively, and the relationship of these factors with the staging of brucellosis patients was analyzed. Results The proportions of Tim-3+CD3+CD4+T cells in the control group, acute group, and chronic group were (2.56±1.25)%, (5.14±1.98)%, and (13.66±2.66)%, respectively. The Tim-3 levels in the patients with brucellosis were higher than those in the healthy control group, with the chronic group showing even higher levels, and these differences were statistically significant (P<0.05). The levels of IL-10 and TGF in the patient group were higher than those in the healthy control group, with the chronic group exhibiting significantly higher levels of IL-10 and TGF-β than the acute group, also presenting statistically significant differences (P<0.05). The areas under the ROC curve for predicting chronic brucellosis with Tim-3, IL-10, and TGF-β scores were 0.876, 0.865, and 0.663, respectively. Conclusions There are certain differences in the expression of Tim-3, serum IL-10, and TGF-β among patients with brucellosis, with high expression indicating a potential transition to the chronic phase of the disease. Tim-3 has shown the best diagnostic performance. Therefore, as a diagnostic indicator, Tim-3 may provide new ideas and strategies for the treatment and differential diagnosis of brucellosis.