The safest location of the thoracentesis site is between 3-6 ribs in the mid-axillary line, too low may easily affect the diaphragm, which also needs to be decided according to the specific condition. Thoracentesis is suitable for simple spontaneous pneumothorax and pleural effusion. For patients with spontaneous pneumothorax, gas will accumulate in the upper part of the lung field with the action of gravity, so puncture can be chosen at the second intercostal area in the midclavicular line, and for patients with pleural effusion, the lateral chest wall and posterior lateral chest wall are usually chosen. For encapsulated pleural effusion, guided puncture can also be performed under CT and ultrasound localization. During the puncture, care should be taken to insert the needle along the upper edge of the inferior ribs to avoid damage to the intercostal nerves and blood vessels. When there is a clear sensation of falling, it proves that the chest cavity has been entered and can be retrieved. However, during the puncture, the patient should be advised to avoid coughing vigorously to avoid collateral damage to the lung tissue.