Clinically, pleural effusion is divided into small, medium and large amounts. Generally, an effusion of less than 500 ml is called a small amount of pleural effusion, which is often not treated and simply given for observation. When the pleural effusion is 500-1000ml, chest puncture is often required to extract the pleural effusion to reduce the patient’s symptoms. When the pleural effusion is greater than 1000 ml or more, then puncture should be performed. Of course, specific problems should be analyzed, and the most important thing is to find the causes and symptoms that cause pleural effusion and find the root cause so that the problem of pleural effusion can be better solved. Puncture only solves the specimen problem, and does not solve the underlying problem.