Objective To investigate thevalueof Interferon- gamma release assay inthe diagnosisof tuberculous pleurisy. Meth-ods176cases of tuberculous pleurisypatientswere selected as experimental group,158cases of non tuberculous patientsas control group.The results of the Interferon- gamma release assay wereobservedintwogroups;to analyze sensitivity andspecificity in?thediagnosisoftubercu-louspleurisy.Results The sensitivity and specificityof Interferon- gamma release assay were 87.5%, 82.9%. respectively;The positive pre-dictive value and negative predictive value were:85.1%, 85.6%;Conclusion Interferon- gamma release assay has higher value on diagnosis of tuberculous pleurisy.