Patients will develop pleural effusion, i.e. fluid in the lungs, after suffering from lung cancer, and these patients are advanced patients once they develop pleural effusion. There are several treatment methods for pleural effusion, as follows: 1. firstly, we should clarify whether it is malignant pleural effusion or exudative pleural effusion, if it is reactive leaky pleural effusion, no tumor cells exist, drainage can be done; 2. if it is clear that it is malignant pleural effusion, that is, the tumor metastasizes to the pleura, resulting in abnormal exudation of capillaries on the pleura, which is equivalent to the leakage of water from blood into the pleural cavity, causing pleural effusion. It causes the occurrence of pleural effusion. At the same time, there are more tumor cells in the pleural effusion, through the drainage of pleural effusion, malignant tumor cells can be found in the pleural effusion, which can be clearly identified as malignant pleural effusion. Clinical practice proves that heat therapy plus chemotherapy has good effect on pleural effusion or peritoneal effusion. By heating chemotherapy drugs through heat perfusion into the chest cavity, it can enhance the penetration of drugs in the chest cavity, thus achieving high level of killing of tumor cells and controlling the further production of pleural effusion. Chemotherapeutic drugs produce fibrotic effect in the thoracic cavity, which helps the adhesion closure of the thoracic cavity. Once the closure of the chest cavity occurs, water cannot easily leak out into the chest cavity and pleural effusion can be controlled. Because pleural effusion, if large, can cause a series of symptoms in patients, especially compression of cardiovascular circulation, the pressure causes poor cardiovascular circulation, which can produce a series of symptoms, such as chest tightness and shortness of breath. The production of pleural effusion and closure of the chest cavity can be controlled by intrathoracic chemotherapy or circulatory heat perfusion, and these symptoms can be effectively controlled.