Abstract: Objective To investigate the clinical application of IFN-γ release test in diagnosis of pulmonary tuberculosis. Methods The concentration of mycobacterium tuberculosis specific IFN-γ in peripheral blood was detected by QFT-G array. The M. tuberculosis DNA loads were examined by FQ-PCR. The results were compared PPD test. Results The sensitivity of QFT-G array, FQ-PCR and PPD was 91.4%、84.2% and 78.9%; the specificity was 86.9%、80.8% and 54.8%; the positive predictive value was 91.0%、92.2% and 71.1%; the negative predictive value was 66.2%、75.4% and 46.3%, and the accuracy was 87.8%、85.0% and 59.6%.Conclusion Compared with FQ-PCR and PPD, QFT-G array had more level of sensitivity, specificity and accuracy, and it may be used as a valued index to evaluate tuberculosis infection.