Recently, the Department of Respiratory Medicine of our hospital used thoracoscopy to diagnose a difficult case. The patient has now been transferred to the Department of Hematology for further treatment with remarkable results. The patient, an elderly male, was admitted to the hospital with “cough and sputum for 1 month, accompanied by chest tightness and breathlessness for more than 10 days”. Before admission, he had been hospitalized in a local hospital for several times, but no clear diagnosis was made. He came to our hospital for further consultation and treatment. Zhang Caijing, Department of Respiratory Medicine, Shandong Qianfo Mountain Hospital Chest X-ray showed: 1, bilateral lung infection; 2, bilateral pleural effusion (small amount) Pulmonary CT showed: 1, pleural effusion and incomplete expansion of the lower lung; 2, pericardial effusion (small amount). After admission, the patient was given closed drainage of the chest cavity and given symptomatic and supportive treatment such as anti-infection, diuresis and decongestion, and sputumification. Pathological results of pleural fluid were sent for multiple times: no cancer cells were detected. Comprehensive examination was considered as: abscess chest? Tuberculous pleurisy? After 7 days of treatment, the pleural fluid did not decrease, and the lung CT review showed: malignant tumor of the mediastinum and enlarged lymph nodes in both mediastinal hilum, considering the possibility of malignant lymphoma, and not excluding thoracic adenocarcinoma and lymph node metastasis. In order to clarify the diagnosis, thoracoscopy was performed in the respiratory lumpectomy room of our hospital. No intrathoracic adhesions and encapsulated fluid were seen. The pleura of the dirty and wall layers was not bright. A biopsy of the cribriform pleura was taken at the posterior costophrenic sinus and sent for examination. Thoracic histocytology brush results: cancer cells were detected; pathological results of chest wall tissue and chest drains taken by thoracoscopy showed: pleural tissue, healthy spleen hyperplasia, focal lymphocytic infiltration, inclined to T-cell non-Hodgkin’s malignant lymphoma. Combined with the patient’s immunohistochemical staining and other examination indexes, the final clear diagnosis was: T-cell non-Hodgkin’s malignant lymphoma. Introduction of endoscopic technique: Endoscopic thoracoscopy is mainly used for the diagnosis and treatment of patients with pleural effusion, mesothelioma and recurrent pneumothorax that cannot be confirmed by non-invasive methods. This technique can be performed under local anesthesia in the endoscopy room, and the patient can breathe on his own and be conscious during the whole process, without the need for general anesthesia and single-lung mechanical ventilation, without the participation of anesthesiologists, with the characteristics of small incision, less intraoperative bleeding, quick recovery and less pain, and relatively inexpensive. The medical staff of our department is technically solid and experienced, and since this technique was launched, more than 20 cases of malignant pleural effusion have been diagnosed. In addition, with the support and cooperation of the hospital, the hardware base of bronchoscopy in our department has become stronger and stronger. Now we have the most advanced international imported thoracoscope and TV camera technology. It has won the satisfaction of patients and their families many times, and has been unanimously affirmed by the peers.