Objective To investigate the effect of improving immunity in the treatment of chronic brucellosis,and to analyze and evaluate its clinical curative effect.Methods A patient with chronic brucellosis was treated with Mongolian medicine combined with chemical drugs to enhance immunity.The clinical symptoms,serological antibodies,Brucella DNA and immune function were compared before and after treatment.The specific antibody against Brucella in serum was detected by tube agglutination test (SAT) and tiger red plate agglutination test (RBPT).Brucella DNA in serum and blood cells was detected by PCR,and the peripheral blood lymphocyte subsets were detected by flow cytometry.Immuno-luminescence technique was used to detect serum immunoglobulin and complement components.Results After treatment,the clinical symptoms such as cold back,fatigue,and joint pain disappeared completely,and the results of serum specific antibodies against Brucella were SAT 1 ∶ 50 (++)and RBPT (+) with no changes before and after treatment,and the results of cells and serum were both negative after treatment though the results of DNA detection of Brucella were cell positive and seronegative before treatment.The results of immunological function test showed that γδT cells decreased to 9.50％ after treatment compared to 14.00％ before treatment,and the percentage of monocytes and Treg cells were 5.59％ and 7.33％ after treatment,which were higher than 3.35％ and 4.72％ of before treatment,and the level of complement C3 was 0.79 g/L before treatment and 0.91 g/L after treatment that was returned to normal reference range (0.88 ～ 2.01 g/L).Conclusion The patients with chronic brucellosis can improve their clinical treatment by improving immunity.