Objective To detect the serum levels of tumor necrosis factor-alpha (TNF-α) and interferengamma (IFN-γ) in brucellosis patients and to study the Th1 immune response in acute and chronic patients.Method Serum levels of TNF-alpha and IFN-gamma of 110 brucellosis patients,including 58 acute brucellosis patients and 52 chronic brucellosis patients,were measured by enzyme linked immunosorbent assay (ELISA) from 2014 to 2015 in Zhangjiakou Infectious Disease Hospital.Results The serum levels of TNF-alpha and IFN-gamma of 58 acute brucellosis patients were (38.2± 3.6) pg/L and (31.3 ± 3.7) ng/L,respectively;the serum levels of TNF-alpha and IFN-gamma of 52 chronic brucellosis patients were (12.4 ± 2.6) pg/L and (8.8 ± 3.4) ng/L,respectively.The differences were statistically significant between acute and chronic patients (t =43.216,33.809,all P ＜ 0.05).The early cure rate,early base cure rate,improvement rate and inefficiency rate were 36.2％ (21/58),32.7％ (19/58),25.9％ (15/58)and 5.2％ (3/58),respectively in acute patients.Inversely,they were 17.3％ (9/52),13.5％ (7/52),15.4％ (8/52)and 53.8％ (28/52),respectively in chronic patients.The therapeutic effect was better in acutepatients than chronic patients (x2 =4.937,5.657,all P ＜ 0.05).Conclusion It seems that acute brucellosis patients have a higher serum levels of TNF-alpha and IFN-gamma and a better prognosis due to effective Th1 immune response,and chronic brucellosis patients are associated with poor outcome due to deficiency of Th1 immune response.