Thoracentesis, as a treatment and diagnostic measure when pleural effusion is present, has fewer complications if properly diagnosed and properly operated for treatment, but still has certain contraindications. The main contraindications to thoracentesis are: I. Those with severe cardiac insufficiency, and factors such as nervousness during puncture, which may have an effect on severe coronary artery disease and severe cardiac insufficiency. II. In those who cough violently and have difficulty in positioning, the thoracentesis needle may accidentally puncture the organs and tissues in the chest cavity. Third, there is inflammation at or near the puncture site, and the puncture may cause the spread of inflammation. Fourth, when a tumor is suspected at the puncture site, the puncture should also pay attention to the puncture, which may cause the tumor to spread along the needle tract and other parts. V. Patients suffering from severe coagulation disorders, such as hemophilia patients, puncture may cause severe bleeding. Sixth, young children and children who are not sedated and not very cooperative should also be punctured with caution.