The indications for thoracocentesis are categorized into diagnostic puncture and therapeutic puncture. Diagnostic puncture is generally used in the following two situations: First, when the patient is suspected of having pneumothorax, hemothorax or pyothorax, and because of some special circumstances, there is no condition for imaging examination, diagnostic puncture can be performed. For patients with pleural effusion, a small amount of fluid can be drawn out for laboratory tests to clarify the nature of the effusion and provide a basis for the diagnosis of the disease. Therapeutic puncture includes: 1. Pneumothorax, hemothorax, pyothorax, etc., which requires puncture to extract gas and fluid to alleviate the chest symptoms. 2. For pleural effusion caused by malignant tumors invading the chest wall, the fluid can be extracted, and then chemotherapeutic drugs can be instilled into the chest cavity or pro-adhesive drugs can be played.