Pulmonary effusion, also known as pleural effusion. Its causes are many. For example, lung infection, tuberculosis, malignant tumor, hypoproteinemia, and chest trauma. Because the causes of pleural effusion are different, the treatment needs to be different. Most of them are more troublesome to treat. For example, pulmonary infections and tuberculosis diseases are inflammatory diseases, therefore, the treatment is in principle to treat the primary disease and anti-inflammatory and anti-infective anti-TB treatment. Malignant pleural effusion caused by malignant tumor, after pumping and releasing fluid, often a large amount of fluid is formed again within a short period of time, which requires repeated puncture and aspiration or continuous closed drainage treatment of the chest cavity, as well as identification of the cause and selection of comprehensive treatment means such as surgery to remove the lesion or radiotherapy, chemotherapy or combination of radiotherapy and chemotherapy. In patients with hypoproteinemia, the first step is also to treat the primary disease, and intravenous albumin supplementation is required along with fluid aspiration. Traumatic pleural effusion often occurs rapidly and requires treatment in the hospital as soon as possible, such as hemostasis, closed chest drainage, and emergency open-chest exploration to stop bleeding. In summary, because the causes of pleural effusion are different, the treatment needs to be treated separately. Most of the treatments are tricky and emergency surgery may be required if necessary.