本文介绍应用PCR(聚合酶链反应)技术检测结核性胸水52例、癌性胸水15例,并与涂片镜检和分离培养对比。PCR检测结核性胸水阳性率28.8％,涂片镜检为3.9％,培养均阴性。癌性胸水三种方法均为阴性。表明PCR是快速检测胸水结核杆菌有力手段 This article describes the application of PCR (Polymerase Chain Reaction) detection of tuberculous pleural effusion in 52 cases, 15 cases of cancerous pleural effusion, and smear microscopy and isolation culture comparison. PCR detection of tuberculous pleural effusion positive rate of 28.8%, smear microscopy was 3.9%, were negative. Three methods of cancerous pleural effusion were negative. PCR is a powerful tool for rapid detection of Mycobacterium tuberculosis