If the pleural effusion is characterized as exudate after laboratory tests, then the cause of the pleural effusion lies in the pleura itself, and pleural biopsy is generally chosen to confirm the diagnosis, because pathological diagnosis is the gold standard for diagnosing this disease. The main means of performing pleural biopsy are pleural biopsy needle, small incision pleural biopsy, thoracoscopic pleural biopsy, and open chest pleural biopsy. The preferred method of pleural biopsy is pleural biopsy needle, which is non-invasive and low cost. The commonly used pleural biopsy needle is Abram needle, which is more painful for patients when taking biopsy tissues and has a low positive rate. This method has been summarized by me in a paper published in “Chinese Journal of Oncology and Rehabilitation, 2005, No. 1” – Application of TSK lung tissue biopsy needle in unexplained pleural disease. Secondly, small incision pleural biopsy, which is done under local anesthesia and requires a certain level of thoracic surgery, can be used instead of this method in hospitals without thoracoscopy. In some patients, pleural biopsy may not be necessary if Mycobacterium tuberculosis or common bacteria can be found in the pleural fluid, but each patient needs to be guided by the clinician.