The role of thoracic puncture is as follows: I. Diagnostic puncture. Diagnostic puncture can be performed if the diagnosis of pleural fluid is unknown, the nature is difficult to determine or there is a mass in the chest cavity, and cytological examination is needed to make a clear diagnosis. Second, therapeutic puncture. For the pressure symptoms caused by large amount of pleural fluid, or closed pneumothorax or hemothorax caused by chest injury, or the early stage of acute abscess chest, therapeutic puncture can be performed to relieve the patient’s symptoms. Third, intrapleural drug delivery. For some patients with pleurisy or chest tumors, thoracentesis can be performed to inject antibiotics or antitumor drugs into the chest cavity for treatment.