Abstract: Objective To analyze CD4⁺CD25⁺ regulatory T cell(Treg) in the peripheral blood of patients with pulmonary tuberculosis and explore its clinical significance. Methods A series of 84 pulmonary tuberculosis patients were detected by flow cytometry with multicolor fluorescence technology for CD4⁺CD25⁺ regulator T cell,with 29 healthy persons as control group.The differences were analyzed between types of pulmonary tuberculosis,bacteriologically positive and negative,initial treatment and retreatment. Results The percentage of CD4⁺CD25⁺ regulator T cell of pulmonary tuberculosis patients(10.81±2.65) was significantly higher than that of controls(P<0.05).The difference between bacterially positive and negative and between types was statistically significant(P<0.05).The difference between initial treatment and retreatment was certain but not significant(P>0.05). Conclusion CD4⁺CD25⁺ regulator T cell can be used as indicator of the immune function in pulmonary tuberculosis patients.It is of clinical significance for the observation of immune status,medication and curative effect on pulmonary tuberculosis patients.