There are three main differences between pleural effusion and pneumothorax: 1) the causes leading to pleural effusion or pneumothorax are not exactly the same; 2) the clinical manifestations have their own differences; 3) the treatment methods also have their own characteristics. Pleural effusion is the appearance of fluid in the pleural cavity, which can be due to the patient’s heart failure, hypoproteinemia, or the involvement of tuberculous infection or tumor cells in the elderly, leading to the appearance of pleural effusion. The most common cause of pneumothorax is a small rupture in the pulmonary blister, the lung leaks like a balloon, the gas leaks into the pleural cavity and a pneumothorax appears, and a defect in the chest wall caused by trauma or stab wounds can also appear as a pneumothorax. dyspnea, while pneumothorax is usually more acute dyspnea. The treatment method is not exactly the same either. The place where the tube is placed for pneumothorax treatment is usually at the top of the chest cavity, where the gas goes higher and the water flows lower, so the location where the tube is placed or the drainage is usually at the bottom of the chest cavity for patients with pleural effusion.